Zoning and the Police Power

Chapter 28 examined the judicial regulation of conflicting land uses. That regulation is retrospective, particular, and expensive: it operates after the conflict has arisen, between the two owners before the court, and only at the cost of litigation. Comprehensive zoning is the legislative answer to those three defects. It operates prospectively, generally, and administratively, by dividing a municipality into districts and prescribing in advance what may be built in each and how large it may be.

The doctrinal question this chapter answers is by what authority a legislature may tell an owner in fee simple absolute what he may do with his land, and what limits the Constitution and the state enabling statutes place on that authority. The answer to the first question is the police power. The answer to the second occupies the remainder of the chapter, and continues into Chapter 30, where regulation that goes “too far” becomes a taking requiring compensation.

1. Zoning is an exercise of the police power, not of eminent domain. The police power regulates without compensating; eminent domain appropriates and must compensate. The line between them is the subject of Chapter 30.
2. The police power is an inherent attribute of state sovereignty. It is not conferred by the federal Constitution; the Fifth and Fourteenth Amendments limit it. Municipalities possess it only as delegated by the State.
3. A municipality has no inherent zoning authority. Zoning is valid only if authorized by a state enabling act or home-rule charter, and an ordinance exceeding the delegation is ultra vires without regard to its reasonableness.
4. The Standard State Zoning Enabling Act supplies the template of American zoning. Its 1926 text — districts, uniformity within districts, a purposes clause, a board of adjustment, and notice-and-hearing procedures — remains recognizable in most state codes.
5. Comprehensive zoning is facially constitutional. Village of Euclid v. Ambler Realty Co., 272 U.S. 365 (1926), sustained district zoning against substantive due process attack, holding it invalid only where clearly arbitrary and unreasonable and bearing no substantial relation to public health, safety, morals, or general welfare.
6. A facially valid ordinance may still be invalid as applied. Nectow v. City of Cambridge, 277 U.S. 183 (1928), decided two years after Euclid, invalidated a district boundary as applied to a particular parcel.
7. The ordinance must be uniform within each district but need not be uniform across districts. Uniformity is the statutory guarantee against ad hoc classification of individual parcels.
8. Zoning must be “in accordance with a comprehensive plan.” In the majority of States the phrase is satisfied by the internal coherence of the ordinance itself; a minority, and the Standard City Planning Enabling Act tradition, require consistency with an independently adopted plan.
9. Existing lawful uses become nonconforming, not unlawful. A use lawfully established before the ordinance may continue, but the law disfavours nonconformities and restricts their expansion, resumption after abandonment, and reconstruction after destruction.
10. Amortization of nonconforming uses is permitted in most States. A reasonable period to recoup investment converts termination into regulation rather than confiscation; a substantial minority of States prohibit amortization of nonconforming uses by statute or decision.
11. A variance requires unnecessary hardship arising from the land, not from the owner. Self-created hardship and the mere prospect of greater profit will not support a variance; the classic formulation is Otto v. Steinhilber, 24 N.E.2d 851 (N.Y. 1939).
12. A special exception is a permitted use, not a dispensation. The legislative body has decided the use is appropriate in the district subject to conditions; the board's function is to verify that the stated standards are met.
13. Rezoning of a small parcel for the owner's benefit and against the plan is spot zoning and is invalid. The vice is the singling out of a parcel for treatment inconsistent with the surrounding classification and the plan, not the size of the parcel alone.
14. Flexibility devices are lawful where they preserve legislative standards. Floating zones, planned unit developments, cluster zoning, overlay districts, incentive zoning, and transferable development rights are sustained where the enabling act permits them and the ordinance supplies ascertainable criteria.
15. Conditional zoning is generally valid; contract zoning is not. A municipality may impose conditions on a rezoning, but it may not bargain away its legislative power by binding itself to zone in a particular way.
16. Development rights vest against subsequent zoning changes only on the occurrence of a defined event. The majority rule requires a lawfully issued permit plus substantial expenditure in good-faith reliance; a minority protect the application date by statute.
17. Aesthetic regulation is a legitimate police-power objective in modern law. Historic preservation, sign control, architectural review, and design standards are sustained where the criteria are ascertainable, though vagueness and First Amendment limits are real.
18. Zoning is bounded by superior law. The First Amendment (signs and adult uses), the Free Exercise Clause and RLUIPA, the Fair Housing Act, the equal protection guarantee, state constitutional general-welfare doctrine (Mount Laurel), and the Takings Clause each independently limit an otherwise authorized ordinance.

1. Define the police power, identify its sources, and distinguish it from eminent domain and from the taxing power.
2. Trace the passage from nuisance regulation to comprehensive zoning, and explain why the defects of nuisance litigation produced a legislative solution.
3. State the structure of the Standard State Zoning Enabling Act and identify its surviving elements in modern state codes.
4. Explain the holding, reasoning, and limits of Village of Euclid v. Ambler Realty Co., and reconcile it with Nectow v. City of Cambridge.
5. Describe the anatomy of a modern zoning ordinance: text, map, use districts, bulk and height controls, density, setbacks, and parking.
6. Distinguish cumulative from exclusive zoning and explain the modern preference for exclusive districting.
7. State the majority and minority approaches to the requirement that zoning be in accordance with a comprehensive plan.
8. Explain the legal treatment of nonconforming uses, including expansion, abandonment, destruction, and amortization.
9. Apply the elements of a use variance and an area variance, and distinguish both from a special exception.
10. Identify spot zoning and state the criteria by which courts distinguish it from a valid amendment.
11. Compare the flexibility devices — floating zones, PUDs, cluster zoning, overlays, incentive zoning, and transferable development rights — and state the conditions of their validity.
12. State the majority rule on vested rights and evaluate a developer's position under it.
13. Identify the constitutional and statutory limits on zoning: the First Amendment, RLUIPA, the Fair Housing Act, equal protection, and state general-welfare doctrine.
14. Select the correct forum, standard of review, and remedy for a challenge to a legislative, quasi-judicial, or administrative land use decision.

The authorities below govern the doctrine developed in this chapter. Statutory citation is to the uniform and model texts; state codes vary in numbering but rarely in substance.

• U.S. Const. amend. V (Takings Clause); amend. XIV, § 1 (Due Process and Equal Protection).
• U.S. Const. amend. I (Speech, Free Exercise, Establishment).
• Standard State Zoning Enabling Act (U.S. Dep't of Commerce rev. ed. 1926).
• Standard City Planning Enabling Act (U.S. Dep't of Commerce 1928).
• Religious Land Use and Institutionalized Persons Act of 2000, 42 U.S.C. §§ 2000cc to 2000cc-5.
• Fair Housing Act, 42 U.S.C. §§ 3601–3631, and 24 C.F.R. § 100.500 (discriminatory effects).
• Civil Rights Act of 1871, 42 U.S.C. § 1983 (remedy for deprivation of federal rights).
• Telecommunications Act of 1996, 47 U.S.C. § 332(c)(7) (limits on siting authority).
• Mugler v. Kansas, 123 U.S. 623 (1887); Hadacheck v. Sebastian, 239 U.S. 394 (1915).
• Welch v. Swasey, 214 U.S. 91 (1909); Pennsylvania Coal Co. v. Mahon, 260 U.S. 393 (1922).
• Village of Euclid v. Ambler Realty Co., 272 U.S. 365 (1926); Nectow v. City of Cambridge, 277 U.S. 183 (1928).
• Village of Belle Terre v. Boraas, 416 U.S. 1 (1974); Moore v. City of East Cleveland, 431 U.S. 494 (1977).
• Village of Arlington Heights v. Metropolitan Housing Development Corp., 429 U.S. 252 (1977).
• Penn Central Transportation Co. v. City of New York, 438 U.S. 104 (1978).
• City of Renton v. Playtime Theatres, Inc., 475 U.S. 41 (1986); Reed v. Town of Gilbert, 576 U.S. 155 (2015).
• City of Cleburne v. Cleburne Living Center, Inc., 473 U.S. 432 (1985).
• Southern Burlington County NAACP v. Township of Mount Laurel, 336 A.2d 713 (N.J. 1975); 456 A.2d 390 (N.J. 1983).
• Fasano v. Board of County Commissioners, 507 P.2d 23 (Or. 1973); Otto v. Steinhilber, 24 N.E.2d 851 (N.Y. 1939).

• Daniel R. Mandelker, Land Use Law (6th ed. 2024 supp.).
• Patricia E. Salkin, American Law of Zoning (5th ed. & Supp.) (successor to Anderson).
• Edward H. Ziegler et al., Rathkopf's The Law of Zoning and Planning (4th ed. & Supp.).
• Julian Conrad Juergensmeyer & Thomas E. Roberts, Land Use Planning and Development Regulation Law (4th ed. 2018).
• John R. Nolon & Patricia E. Salkin, Land Use in a Nutshell (2d ed.).
• Robert C. Ellickson, Alternatives to Zoning: Covenants, Nuisance Rules, and Fines as Land Use Controls, 40 U. Chi. L. Rev. 681 (1973).
• Carol M. Rose, Planning and Dealing: Piecemeal Land Controls as a Problem of Local Legitimacy, 71 Calif. L. Rev. 837 (1983).
• Charles M. Haar, In Accordance with a Comprehensive Plan, 68 Harv. L. Rev. 1154 (1955).
• Richard F. Babcock, The Zoning Game (1966).
• Restatement (Third) of Property: Servitudes ch. 3 introductory note (Am. L. Inst. 2000) (private and public controls compared).

The police power is the authority of a sovereign to regulate private conduct and private property in the interest of the public health, safety, morals, and general welfare. It is not created by the federal Constitution and is not among the powers delegated to Congress; it is an attribute of state sovereignty reserved by the Tenth Amendment, and its federal-constitutional significance lies entirely in the limits imposed upon it by the Fifth and Fourteenth Amendments.

Two features of the power are decisive for the law of property. First, it operates without compensation. A regulation that validly restricts an owner's use of land takes nothing from him in the constitutional sense; the owner has no vested right in the continuation of any particular legal regime, and the value the regulation destroys was always held subject to the sovereign's authority to regulate. Second, it is not a power to appropriate. Where the public seeks to acquire land or an interest in land for its own use, the appropriate instrument is eminent domain, and compensation is constitutionally required.

Between those poles lies the field of Chapter 30. Pennsylvania Coal Co. v. Mahon, 260 U.S. 393, 415 (1922), announced the governing proposition that “while property may be regulated to a certain extent, if regulation goes too far it will be recognized as a taking.” This chapter is concerned with regulation that does not go too far: the ordinary law of zoning, its authorization, structure, administration, and non-takings limits.

A municipality possesses no inherent police power. It is a creature of the State, and it may zone only to the extent the State has delegated the authority by enabling act or, in home-rule jurisdictions, by constitutional or charter grant. The consequence is practical and constant: every zoning question begins with the enabling statute, and an ordinance beyond the delegation fails without any inquiry into its wisdom or reasonableness.

The nineteenth century regulated land use through nuisance, supplemented by scattered ordinances directed at particular trades. That regime had three defects, each of which the zoning movement was designed to cure.

The first defect is retrospectivity. Nuisance operates after the conflicting use is established and the investment made, so that the remedy is either an injunction destroying a completed enterprise or damages leaving the injured neighbour to live with the harm. Chapter 28 showed how deeply that dilemma marks the remedial law from Ducktown to Boomer.

The second defect is particularity. A nuisance decree binds the parties before the court and produces no general rule of neighbourhood. The tenth smelter must be litigated as fully as the first, and the owner planning a use cannot learn from the record what he may lawfully build.

The third defect is cost and unpredictability. Nuisance is a standard, not a rule; it is unrecorded and therefore invisible to a title searcher; and its application depends on evaluative judgments about locality and reasonableness that no purchaser can make with confidence in advance.

Zoning answers all three. It speaks before construction rather than after; it speaks generally, by district, rather than to particular parties; and it speaks in rules — height in feet, setback in feet, use by enumerated category — that a purchaser can read from a map. The price of those virtues is rigidity, and the flexibility devices treated in Part III of this chapter are the law's response to that price.

Sanitary regulation supplied the constitutional bridge. Mugler v. Kansas, 123 U.S. 623 (1887), sustained the destruction of the value of a brewery under a prohibition statute; Hadacheck v. Sebastian, 239 U.S. 394 (1915), sustained an ordinance excluding brickmaking from a district of Los Angeles though it reduced the value of the plaintiff's land by an order of magnitude; and Welch v. Swasey, 214 U.S. 91 (1909), sustained height limits differentiated by district. By 1920 the constitutional materials for comprehensive districting were assembled.

The modern American ordinance descends from a single model text. The Advisory Committee on Zoning of the Department of Commerce published the Standard State Zoning Enabling Act (SZEA) in 1922, in revised form in 1926; by 1930 a substantial majority of States had adopted it substantially unaltered. Its influence on the structure of the subject is difficult to overstate: the vocabulary of American zoning law is the vocabulary of a nine-section model statute.

Section 1 is the grant of power: the municipality may regulate the height, number of stories, and size of buildings; the percentage of a lot that may be occupied; the size of yards and open spaces; the density of population; and the location and use of buildings and land for trade, industry, residence, and other purposes.

Section 2 authorizes division into districts and imposes the uniformity requirement: regulations must be uniform for each class of building throughout each district, though they may differ from district to district. Section 3 is the purposes clause, requiring that regulations be made in accordance with a comprehensive plan and designed to lessen congestion, secure safety from fire and panic, promote health and general welfare, provide adequate light and air, prevent overcrowding, avoid undue concentration of population, and facilitate adequate provision of public facilities.

Sections 4 and 5 prescribe procedure: public hearing, notice, and a protest provision requiring a supermajority to override objection by owners of a stated fraction of the affected or adjoining land. Section 6 creates the zoning commission. Section 7 creates the board of adjustment and defines its three functions — appeals from administrative determinations, special exceptions, and variances upon a showing of unnecessary hardship. Sections 8 and 9 address remedies and conflict with other law.

Two consequences follow for the practitioner. First, the tripartite division of decision-making — legislative amendment by the governing body, quasi-judicial relief by the board of adjustment, administrative determination by the zoning officer — is the structure against which every procedural and review question is posed. Second, the enumeration in section 1 is a limit as well as a grant; regulation of a subject not fairly within the enumeration or a home-rule grant is ultra vires.

Village of Euclid v. Ambler Realty Co., 272 U.S. 365 (1926), is the foundational case of American land use law. Ambler Realty held sixty-eight acres in a suburb of Cleveland, held for industrial development in the path of expanding industry, and the village's 1922 ordinance placed much of the tract in districts restricted to residential and light commercial use. The company alleged a reduction in value from $10,000 to $2,500 an acre and attacked the ordinance on its face as a deprivation of property without due process.

The district court held the ordinance unconstitutional in terms that repay reading; it saw the scheme as an attempt to preserve the character of the village at the expense of the individual owner. The Supreme Court reversed. Justice Sutherland's opinion accepted that the ordinance would have been unthinkable a half-century earlier, but reasoned that the police power must be construed in light of conditions: the density and complexity of urban life had created problems that earlier generations did not face, and “regulations, the wisdom, necessity and validity of which, as applied to existing conditions, are so apparent that they are now uniformly sustained, a century ago, or even half a century ago, probably would have been rejected as arbitrary and oppressive.”

The methodological move that decided the case was the analogy to nuisance. The Court reasoned from the law of Chapter 28 that the exclusion of an industrial use from a residential district is a legislative generalization of what a court would decide case by case — the pig in the parlor rather than the barnyard. The legislature having power to abate nuisances one at a time, it has power to prevent them wholesale by districting.

The standard of review announced is deferential and remains the black letter: an ordinance is invalid under the Due Process Clause only if its provisions “are clearly arbitrary and unreasonable, having no substantial relation to the public health, safety, morals, or general welfare.” Where the question is fairly debatable, the legislative judgment controls.

Two features of the opinion have proved consequential in ways the Court did not anticipate. The first is its acceptance of the apartment house as a legitimate object of exclusion from single-family districts — described in the opinion as “mere parasite” in relation to the detached-house neighbourhood — which supplied the doctrinal ancestor of the exclusionary practices treated at § 29.21. The second is the Court's careful confinement of the holding to the ordinance in general terms, expressly reserving the possibility that specific applications would be invalid.

Nectow v. City of Cambridge, 277 U.S. 183 (1928), decided two Terms after Euclid, redeemed the reservation. A district boundary ran through the plaintiff's land, placing a 100-foot strip in a residential district and defeating a contract for sale of the whole for industrial use. A master found that the strip's inclusion served no substantial public purpose in the circumstances, the surrounding land being devoted to industry and a railroad.

The Court held the ordinance invalid as applied. The Euclid standard was reaffirmed — the invasion of property rights must find justification in some aspect of the police power asserted for the public welfare — but on the master's findings no such justification existed for the strip in question.

The lesson is structural and remains sound a century later. A comprehensive ordinance is presumptively valid, and the presumption is nearly conclusive as to the general scheme, but the line-drawing that districting necessarily requires may fail at the margin. Practically, the as-applied due process challenge has become a minor part of American land use litigation, displaced by the regulatory takings framework of Chapter 30, by state-law arbitrariness review, and by the constitutional guarantees at §§ 29.20 through 29.22 — but the doctrinal opening Nectow created remains.

A zoning ordinance consists of two instruments that must be read together. The text states the districts, the uses permitted in each, the dimensional requirements, the procedures, and the definitions. The map assigns every parcel in the municipality to a district. Neither is intelligible alone: the text tells the reader what an R-2 district permits, and the map tells him whether his parcel is in one.

The definitional article is the most heavily litigated portion of most ordinances, because the classification of a proposed use as “family,” “professional office,” “warehouse,” “restaurant,” or “adult use” is dispositive and is frequently contestable. Ordinances are construed like statutes, with the additional canon, applied in most States, that ambiguity is resolved in favour of the free use of land — a canon of considerable practical weight, though several jurisdictions apply the contrary canon of deference to the administering agency.

The map is amended parcel by parcel over the life of the ordinance, and the accumulation of amendments is where the tension between planning and dealing described by Rose becomes visible. Section 29.14 treats the limits on that process.

Zoning regulates along two independent axes. Use controls determine what activity may be conducted; bulk and dimensional controls determine the size, shape, and placement of what may be built. Both derive from section 1 of the SZEA, and a proposal must satisfy both.

Use districts are conventionally designated by letter and number: R for residence, C or B for commercial, I or M for industrial, A for agricultural, with numerical subdivisions of increasing intensity. Dimensional controls comprise minimum lot area and lot width, minimum front, side, and rear yards (setbacks), maximum height in feet or stories, maximum lot coverage, and floor area ratio (FAR) — the ratio of gross floor area to lot area, the principal instrument of bulk control in urban ordinances.

Density is controlled directly by dwelling units per acre and indirectly by minimum lot size and minimum floor area per dwelling. Off-street parking and loading requirements, landscaping and buffering standards, sign regulations, and performance standards for noise, vibration, glare, and emissions complete the ordinary apparatus.

The distinction between the use and bulk axes carries doctrinal weight, because most jurisdictions apply a materially lower standard to an area variance than to a use variance. Section 29.12 develops the point.

The 1920s ordinance, including Euclid's, was cumulative or pyramidal. Districts were arranged in a hierarchy from the single-family residence at the apex to heavy industry at the base, and each district permitted its own uses together with all uses permitted in the districts above it. A factory district accordingly permitted houses; a residence district permitted nothing but residences.

The premise of cumulative zoning was that residential use is the highest and most protected use and that no harm can come from admitting a higher use to a lower district. Experience falsified the premise. Housing built in industrial districts is exposed to precisely the conditions from which zoning was meant to protect it; residents so situated then press for regulation of the industry that preceded them; and the industrial land supply is consumed by uses that could locate elsewhere.

Modern ordinances are therefore predominantly exclusive: each district permits only its enumerated uses, and industrial districts exclude residences as firmly as residential districts exclude industry. The validity of exclusive industrial districting was contested in mid-century and is now settled, the leading decision being People ex rel. Skokie Town House Builders, Inc. v. Village of Morton Grove, 157 N.E.2d 33 (Ill. 1959), which sustained exclusion of residential use from an industrial district.

A different question is whether a municipality may exclude a use from its entire territory. Total exclusion of a legitimate use is scrutinized more closely; Pennsylvania's decisions on the point, beginning with Exton Quarries, Inc. v. Zoning Board of Adjustment, 228 A.2d 169 (Pa. 1967), treat a total prohibition as presumptively invalid and require the municipality to justify it. Section 29.21 develops the regional dimension of the same problem.

Section 3 of the SZEA requires that zoning regulations be made “in accordance with a comprehensive plan,” and the phrase has generated a literature of its own. Haar's 1955 article framed the question that the States have answered differently: is the plan an independent document that governs the ordinance, or is the ordinance itself the plan?

The majority answer is the latter. In most States the requirement is satisfied by a showing that the ordinance is internally coherent, rationally related to the municipality's circumstances, and not the product of ad hoc parcel-by-parcel judgment. On that view no separately adopted plan is required, and the phrase functions as a prohibition of arbitrariness rather than as a hierarchy of instruments.

A significant minority of States, by statute, require consistency between zoning and an independently adopted comprehensive plan and make inconsistency a ground of invalidity. California, Oregon, Florida, Washington, and several others have adopted consistency requirements of varying strength, in some instances embedded in a state-level growth management framework with regional review.

The practical significance of the distinction appears in litigation over amendments. Where consistency is mandatory, the plan is the measure of the amendment and the challenger's burden is comparatively light; where the ordinance is its own plan, the challenger must show arbitrariness on the more deferential Euclid standard. Section 29.14 returns to the point in the context of spot zoning, where even non-consistency States treat departure from an adopted plan as strong evidence of invalidity.

Zoning does not stand alone. Two companion regimes, authorized by separate enabling legislation, govern the division of land and the design of individual projects.

Subdivision control conditions the division of a parcel into lots for sale or development on approval of a plat by the planning board. Its historical function was to secure adequate streets, utilities, drainage, and recordable descriptions; its modern function extends to the dedication of land for parks and schools and to the imposition of impact fees. The recording consequences of platting are treated in the recording and title chapters later in this volume; the constitutional limits on exactions are treated in Chapter 30 under Nollan, Dolan, and Koontz.

Site plan review governs the layout of a permitted use on a particular parcel: circulation, parking, landscaping, lighting, drainage, and building placement. Because a site plan applies to a use the ordinance already permits, the reviewing body's authority is generally limited to conditions on design and mitigation, and it may not use the process to deny a permitted use outright — a limit frequently tested and generally enforced.

Official map, capital improvement programming, and adequate public facilities ordinances (concurrency) complete the regulatory apparatus in the more elaborate systems, conditioning approval on the availability of infrastructure capacity.

Every new ordinance encounters uses lawfully established under the prior regime that the new districting does not permit. To terminate them at once would have raised grave constitutional objection in 1926 and would raise it still; every enabling act therefore permits the lawful nonconforming use to continue. The nonconforming use is lawful, not merely tolerated, and the right to continue it runs with the land rather than belonging personally to the owner who established it.

The law nonetheless disfavours nonconformities, on the premise that the district's intended character cannot be achieved while they persist, and the disfavour is expressed in four familiar restrictions.

• No expansion or enlargement. The use may continue at its established scale. The distinction is between intensification of the existing use, which is generally permitted (more customers at the same restaurant), and expansion of the physical or functional envelope, which is not (a second building; a new line of business).
• No change to another nonconforming use. Change is ordinarily permitted only to a conforming use, or, under many ordinances, to a nonconforming use of the same or a more restricted classification on board approval.
• Termination by abandonment or discontinuance. Common-law abandonment requires an intent to abandon plus overt acts; most ordinances substitute a discontinuance provision terminating the right after a stated period of non-use, often six or twelve months, without regard to intent. The two standards produce materially different outcomes and the ordinance controls.
• Termination by destruction. Where the structure housing the use is destroyed beyond a stated percentage of value, the right to resume generally ends; reconstruction is permitted only in conformity.

A distinct category is the nonconforming structure that houses a conforming use — the house built to a five-foot setback in a district now requiring fifteen. Ordinances generally treat it more indulgently than the nonconforming use, permitting maintenance and often reconstruction.

Amortization is the technique of terminating a nonconforming use at the end of a period fixed by the ordinance, on the theory that a period sufficient to recoup the owner's investment converts what would be a confiscation into a permissible regulation of the time of compliance. The device is best understood as the deliberate substitution of a delayed, general termination for the immediate, particular termination that a nuisance decree would work.

The majority position sustains amortization where the period is reasonable in the circumstances. The factors are the nature of the use, the amount invested, the extent of depreciation already realized, the remaining useful life of the structure, the ease of relocation, the harm to the public from continuation, and the length of the period allowed. Nonconforming signs, junkyards, and adult uses are the most common subjects, with periods ranging from months for a sign to years for a structure.

A substantial minority rejects amortization outright. Pennsylvania is the leading example, PA Northwestern Distributors, Inc. v. Zoning Hearing Board, 584 A.2d 1372 (Pa. 1991), holding amortization of a lawful nonconforming use per se confiscatory under the state constitution; several other States have reached the same result by statute. The practitioner must therefore treat amortization as a jurisdiction-specific question and must not assume the majority rule.

The variance is the safety valve of the ordinance, and the constitutional justification for the ordinance's rigidity. Section 7 of the SZEA authorizes the board of adjustment to vary the ordinance where, owing to special conditions, literal enforcement would result in unnecessary hardship, provided the spirit of the ordinance is observed and substantial justice done.

The classical statement of the use variance standard is Otto v. Steinhilber, 24 N.E.2d 851, 853 (N.Y. 1939): the applicant must show (1) that the land cannot yield a reasonable return if used only as zoned, (2) that the plight is due to unique circumstances and not to general conditions in the neighbourhood, and (3) that the use sought will not alter the essential character of the locality. New York has since codified a four-element test adding the absence of a feasible alternative and the self-created-hardship bar.

Three limits recur and account for most denials. First, the hardship must inhere in the land — its shape, topography, soil, or an irregularity of the map — and not in the personal circumstances of the owner. Second, hardship that the owner created, typically by subdividing to produce a substandard lot or by purchasing with knowledge of the restriction, will not support relief; the majority treats purchase with knowledge as not itself disqualifying, but purchase at a price reflecting the restriction is powerful evidence that the claimed hardship is a claim of lost profit. Third, the impossibility of the most profitable use is not unnecessary hardship; the standard is the absence of any reasonable return.

The area variance is governed by a materially lower standard in most jurisdictions, commonly “practical difficulties” rather than unnecessary hardship, and in New York by a statutory balancing of the benefit to the applicant against the detriment to the neighbourhood, considering whether the difficulty is self-created, whether an alternative exists, whether the variance is substantial, and whether it will adversely affect physical or environmental conditions.

A special exception — called a conditional use or special use permit in many States — is a use that the ordinance itself contemplates in the district, subject to conditions and to administrative verification that the conditions are satisfied. Hospitals, schools, churches, gasoline stations, day-care centres, and telecommunications facilities are typical subjects.

The essential point, and the one most frequently misunderstood, is that the legislative judgment has already been made in favour of the use. The board does not decide whether the use belongs in the district; it decides whether the applicant has met the standards the ordinance prescribes. It follows that the applicant's burden is one of compliance rather than of justification, that denial must rest on findings referable to the ordinance's standards, and that general neighbourhood opposition unsupported by evidence bearing on those standards is not a lawful ground of denial.

The chief legal vulnerability of the device is standards. A delegation to a board to grant permits where it finds the use “in the public interest” or “compatible with the neighbourhood,” without more, is attacked as an unlawful delegation of legislative power and as void for vagueness; most courts sustain general standards where the ordinance's purposes clause and context supply content, but the challenge is real and periodically succeeds.

Conditions imposed on a special exception must be reasonably related to the impacts of the use, must be within the enabling authority, and may not be used to extract unrelated public benefits — a limit that converges with the exactions doctrine of Chapter 30.

The zoning map is amended continuously, and most amendments are sought by an owner as to his own parcel. Because the governing body acts by ordinance, the amendment is formally legislative and attracts the deferential Euclid presumption; because it decides the rights of a single owner on an individual application, it has the substance of adjudication. American law has never fully resolved the tension.

The traditional approach applies the presumption of validity and invalidates only spot zoning. Spot zoning is the singling out of a small parcel for a classification different from that of the surrounding area and inconsistent with the comprehensive plan, for the benefit of the owner rather than the community. The factors are the size of the parcel, the degree of the departure from surrounding classifications, the consistency of the change with an adopted plan, the presence or absence of changed conditions justifying the change, and the identity of the benefited party. No factor is dispositive; a small parcel rezoned consistently with a plan is not spot zoning, and a large parcel rezoned in flat contradiction of the plan for a single owner's benefit may be.

The reformist approach, associated with Fasano v. Board of County Commissioners, 507 P.2d 23 (Or. 1973), reclassifies small-parcel rezonings as quasi-judicial. The consequences are procedural and substantive: notice and an opportunity to be heard, an impartial decision-maker, a record, findings, and a burden on the proponent to show conformity with the plan and a public need. Oregon, Washington, Colorado, Florida, and a number of other States have adopted the approach in some form; the majority retains the legislative characterization.

A related doctrine of decreasing importance is the change-or-mistake rule, applied strictly in Maryland and a few other States, which permits amendment only on proof of a substantial change in the character of the neighbourhood since the original zoning or of a mistake in the original ordinance.

Municipalities routinely rezone on conditions: the developer records a covenant limiting the parcel to one of the uses the new district permits, agrees to buffering and access restrictions, or dedicates a right of way. The nomenclature in the cases is not uniform, but the operative distinction is well settled.

Conditional zoning, in which the municipality unilaterally imposes conditions on the reclassification or accepts a covenant running with the land from the owner, is generally valid. It is defended as a means of granting the reclassification while mitigating its impacts, and thereby of avoiding the all-or-nothing choice that unconditioned amendment would force. Restrictions so imposed are ordinarily enforceable both as zoning and, where recorded, as servitudes under the principles of Chapter 23.

Contract zoning, in which the municipality binds itself by agreement to enact or maintain a particular classification, is generally invalid. The police power is held in trust for the public and cannot be bargained away; a legislature cannot contract away its successors' authority to legislate; and the bargain displaces the statutory hearing process by which the public participates. The vice is the surrender of legislative discretion, not the existence of negotiation.

The practical line is therefore whether the municipality has promised. A recorded covenant from the owner conditioning the use of the parcel is valid; a written agreement obliging the council to adopt the amendment is not. A growing number of States have displaced the problem by statute through development agreement legislation, which expressly authorizes binding agreements freezing the applicable regulations for a term in exchange for stated public commitments, subject to notice, hearing, and recording.

Euclidean districting achieves predictability by rigidity, and the cost of the rigidity is that it cannot accommodate large or mixed projects, unusual sites, or objectives (open space, affordability, historic character) that do not correspond to district lines. Four devices supply flexibility within the legislative framework.

• Floating zone. A district is created in the text with standards and conditions but is not initially mapped; it is “landed” on a particular parcel by amendment when an applicant satisfies the criteria. Sustained in Rodgers v. Village of Tarrytown, 96 N.E.2d 731 (N.Y. 1951), and now general, though it is vulnerable to spot-zoning attack when the criteria are thin.
• Planned unit development (PUD). The whole tract is approved as a unit under negotiated standards, permitting mixed uses, varied housing types, and dimensional departures in exchange for open space and coordinated design. Validity depends on enabling authority and on ascertainable standards constraining the approving body.
• Cluster zoning. Density is fixed for the tract as a whole and the units are concentrated on part of it, the balance being preserved as open space. Because overall density is unchanged, cluster zoning is the least legally contentious of the flexibility devices.
• Overlay district. A supplemental set of regulations is mapped over the underlying districts, adding requirements without displacing them — floodplain, historic, airport approach, hillside, wellhead protection, and corridor overlays are typical.

Two further devices operate on development rights themselves. Incentive or bonus zoning grants additional floor area or height in exchange for a public amenity — plaza, arcade, affordable units, transit improvement — and is the standard instrument of large-city zoning since New York's 1961 resolution. Transferable development rights (TDR) sever the unused development potential of a restricted parcel and permit its sale for use on a receiving parcel; the Supreme Court treated a TDR entitlement as relevant to the takings calculus in Penn Central Transportation Co. v. City of New York, 438 U.S. 104 (1978), and the mechanism is central to historic preservation and farmland protection programmes.

Early decisions denied that aesthetics alone could support the police power, requiring that appearance regulations be justified by health, safety, or property values. That position has been abandoned. The modern rule, anticipated by the Supreme Court's statement in Berman v. Parker, 348 U.S. 26, 33 (1954), that the public welfare embraces values “spiritual as well as physical, aesthetic as well as monetary,” treats aesthetic objectives as legitimate ends in themselves in the great majority of States.

Historic preservation is the most secure application. Penn Central sustained New York City's landmarks law against a takings challenge to the denial of a fifty-five-storey tower above Grand Central Terminal, holding that the regulation was part of a comprehensive plan, applied to a broad class of properties, permitted a reasonable return from the existing use, and left transferable development rights available. Chapter 30 develops the takings analysis; for present purposes the point is that landmark designation and certificate-of-appropriateness review are ordinary and valid exercises of the police power.

Architectural and design review is more contested, and the contest is about standards rather than about ends. Ordinances directing a board to prevent structures “inharmonious” with their surroundings or “detrimental to property values” have been sustained in many States and struck down as unconstitutionally vague or as unlawful delegations in others. The defensible ordinance states criteria referable to observable features — materials, roof pitch, fenestration, setback rhythm, relationship to the streetwall — rather than to the reviewer's taste.

Sign regulation sits at the intersection of aesthetics and the First Amendment and is treated at § 29.20.

An owner has no right to the continuation of existing zoning, and a municipality may ordinarily change the rules while a project is in planning. The question is when a project acquires immunity from a subsequent change: at what point, in the standard formulation, do rights vest.

The majority rule is the permit-plus-reliance test. Rights vest when the owner has obtained a lawfully issued building permit and has thereafter made substantial expenditures or incurred substantial obligations in good-faith reliance on it. Preliminary expenses — options, architectural drawings, engineering studies, financing costs — are generally insufficient; commencement of physical construction is generally sufficient. The requirement that the permit be lawfully issued is strict: rights do not vest under a permit issued in error, though estoppel may occasionally supply the deficiency where the municipality's conduct induced the reliance and the equities are strong.

Two minority approaches deserve note. Several States protect the applicant from the date of a complete application, by statute, so that the regulations in force when the application is filed govern its disposition — the “permit application” or “pending ordinance” rule reversed. California follows a notably strict version of the majority rule, requiring a building permit and substantial work, illustrated by Avco Community Developers, Inc. v. South Coast Regional Commission, 553 P.2d 546 (Cal. 1976); the development agreement statutes discussed at § 29.16 were enacted in direct response.

Conversely, the pending ordinance doctrine, followed in a number of States, permits a municipality to deny a permit that conforms to present law where an amendment prohibiting the use has been formally initiated. Some States reject the doctrine and require issuance under the law in force at the time of application; the divergence is sharp and jurisdiction-specific.

Zoning that regulates expression or religious exercise is subject to constraints external to land use law, and the analysis is governed by First Amendment doctrine rather than by the Euclid standard.

Adult entertainment uses may be dispersed or concentrated by ordinance where the regulation is aimed at secondary effects — crime, blight, declining property values — rather than at the content of the expression. Young v. American Mini Theatres, Inc., 427 U.S. 50 (1976), sustained dispersal; City of Renton v. Playtime Theatres, Inc., 475 U.S. 41 (1986), sustained concentration, treating the secondary-effects ordinance as content-neutral time, place, and manner regulation and requiring that reasonable alternative avenues of communication remain. A municipality may not use the doctrine to exclude such uses entirely.

Sign regulation was transformed by Reed v. Town of Gilbert, 576 U.S. 155 (2015), which held that an ordinance distinguishing among temporary signs by their subject matter — ideological, political, directional — was content-based on its face and subject to strict scrutiny without regard to the municipality's benign motive. City of Austin v. Reagan National Advertising of Austin, LLC, 596 U.S. 61 (2022), narrowed the reach of Reed by holding that the on-premises/off-premises distinction is not content-based merely because it requires reading the sign to determine its location relationship. The drafting lesson is durable: regulate size, height, illumination, number, and location, and avoid classification by message.

Religious land use is governed by the Religious Land Use and Institutionalized Persons Act of 2000. Its equal terms provision forbids treating a religious assembly on less than equal terms with a nonreligious assembly; its nondiscrimination and unreasonable-limitations provisions forbid discrimination among denominations and the total exclusion of religious assemblies from a jurisdiction; and its substantial burden provision requires that a land use regulation imposing a substantial burden on religious exercise be justified by a compelling interest pursued by the least restrictive means. RLUIPA has materially altered the practical treatment of churches, synagogues, mosques, and religious schools under local ordinances.

Federal statutory limits operate in the same fashion elsewhere: the Telecommunications Act of 1996 constrains the siting of wireless facilities, forbidding effective prohibition of service and requiring that denials be in writing and supported by substantial evidence.

The capacity of zoning to exclude is not incidental to it; it is what districting does. Minimum lot sizes, minimum floor areas, prohibitions of multifamily and manufactured housing, and bedroom limits raise the cost of entry to a municipality and, in the aggregate, allocate low- and moderate-income households to other jurisdictions. Whether that consequence is lawful has been the central normative question of American land use law since the 1960s.

Federal constitutional doctrine offers a narrow avenue. Village of Arlington Heights v. Metropolitan Housing Development Corp., 429 U.S. 252 (1977), held that a refusal to rezone for subsidized housing violates equal protection only on proof of discriminatory purpose, disparate impact alone being insufficient, and identified the evidentiary factors — impact, historical background, sequence of events, departures from normal procedure, and legislative history — by which purpose may be proved. Wealth is not a suspect classification and housing is not a fundamental right for these purposes, so rational-basis review governs otherwise. City of Cleburne v. Cleburne Living Center, Inc., 473 U.S. 432 (1985), nevertheless invalidated the denial of a permit for a group home for persons with intellectual disabilities as resting on irrational prejudice.

The Fair Housing Act is the more effective federal instrument. It reaches zoning decisions, permits proof by discriminatory effect as well as intent, and requires reasonable accommodation in rules and policies for persons with disabilities — the provision under which group homes are most often protected. Texas Department of Housing & Community Affairs v. Inclusive Communities Project, Inc., 576 U.S. 519 (2015), confirmed the availability of disparate-impact liability while imposing a robust causality requirement and cautioning against liability based on statistical disparity alone.

The most consequential doctrine is a matter of state constitutional law. Southern Burlington County NAACP v. Township of Mount Laurel, 336 A.2d 713 (N.J. 1975), held that a developing municipality's land use regulations must make realistically possible an appropriate variety and choice of housing, including its fair share of the regional need for low- and moderate-income housing, because the zoning power is delegated to be exercised for the general welfare — and the general welfare is not confined to the municipality's own residents. Mount Laurel II, 456 A.2d 390 (N.J. 1983), supplied remedies, including the builder's remedy, and the doctrine was subsequently administered by statute through the Fair Housing Act of 1985 and the Council on Affordable Housing.

Other States have declined to follow. New York's Berenson v. Town of New Castle, 341 N.E.2d 236 (N.Y. 1975), requires consideration of regional needs without imposing a fair-share obligation; Pennsylvania's line from National Land & Investment Co. v. Kohl, 215 A.2d 597 (Pa. 1965), invalidates exclusionary devices in individual cases without a systemic remedy. Legislative approaches predominate elsewhere: Massachusetts' comprehensive permit statute (Chapter 40B), California's housing element and builder's remedy regime, and the recent wave of state preemption statutes authorizing accessory dwelling units and small multifamily buildings by right notwithstanding local ordinances.

Single-family districting requires the ordinance to define the family, and the definition determines who may live in the district. Two decisions define the federal constitutional field.

Village of Belle Terre v. Boraas, 416 U.S. 1 (1974), sustained an ordinance restricting occupancy to traditional families or to no more than two unrelated persons, applied to six unrelated university students. Justice Douglas treated the classification as economic and social legislation subject to rational-basis review, and found the ends — quiet, low density, clean air, family values — legitimate.

Moore v. City of East Cleveland, 431 U.S. 494 (1977), invalidated an ordinance whose definition of family was so narrow that a grandmother could not live with two grandsons who were cousins rather than brothers. The plurality held that the ordinance intruded on the freedom of personal choice in matters of family life protected by substantive due process, and that the constitution protects the extended family and not merely the nuclear one.

State constitutional law has moved further. New Jersey's State v. Baker, 405 A.2d 368 (N.J. 1979), and California's City of Santa Barbara v. Adamson, 610 P.2d 436 (Cal. 1980), invalidated unrelated-persons limits, and a substantial number of States now require functional-family definitions keyed to the manner of living — a single housekeeping unit — rather than to blood, marriage, or adoption. The Fair Housing Act's reasonable-accommodation requirement operates independently to protect group homes for persons with disabilities from occupancy caps of this kind.

The subject has acquired new prominence through state legislation authorizing accessory dwelling units and short-term rental regulation, both of which are enforced through the definition of the household as much as through use classification.

Local zoning is subordinate to state and federal law, and three recurring problems arise from that subordination.

The first is preemption. A state statute may occupy a field — agricultural operations, group homes, manufactured housing, telecommunications, mining, energy facilities, and increasingly housing density — and displace inconsistent local regulation either expressly or by implication. The recent legislative wave authorizing accessory dwelling units and small multifamily construction by right is the most significant contemporary instance.

The second is intergovernmental immunity. Whether a state agency, school district, county, or public utility must comply with municipal zoning is answered by a variety of tests: the superior sovereign rule, the governmental-proprietary distinction, the eminent-domain-power test, and the balancing test associated with Rutgers v. Piluso, 286 A.2d 697 (N.J. 1972), which asks whether the legislature intended the entity to be subject to local control, weighing the nature and scope of the instrumentality, the kind of function, the applicant's legislative authority, the effect on local land use, and the alternatives available.

The third is federal supremacy: federal installations and activities are not subject to local zoning, and federal statutes of the kind discussed at § 29.20 constrain local authority even where no federal instrumentality is involved.

Zoning is administered by three actors, and identifying the actor determines the procedure, the record, and the standard of review.

Exhaustion of administrative remedies is ordinarily a precondition of judicial review, and the requirement has teeth: a landowner who has not sought a variance or an interpretation from the board will usually be turned away, and, in the takings context, will fail the ripeness requirement discussed in Chapter 30.

Standing to challenge a land use decision is broader than the general rule of standing in property litigation. Adjoining and nearby owners are generally presumed aggrieved; competitors are generally not, absent a statute; and taxpayer and citizen standing varies widely. Most States prescribe a short limitations period — thirty, forty-five, or sixty days — for actions in the nature of certiorari challenging a board decision, and the period is jurisdictional in many of them.

On the municipality's side, enforcement proceeds by stop-work order, permit revocation, denial of a certificate of occupancy, civil penalties accruing daily, and injunctive relief; criminal penalties are available under most ordinances and are rarely used. Neighbours may enforce by private action in many States, either by statute or on a showing of special damage of the kind required for a public nuisance action under Chapter 28.

On the owner's side, the traditional remedies are declaratory judgment and certiorari review, with the relief in most States being invalidation of the ordinance as applied rather than an order to permit the specific project. A minority grant site-specific relief, and New Jersey's builder's remedy under Mount Laurel II is the most far-reaching example. Damages are available in the takings framework of Chapter 30, and under 42 U.S.C. § 1983 where a federal right has been violated, subject to the substantive limits on substantive-due-process claims in land use and to municipal liability doctrine.

Two practical points close the topic. First, the choice of theory determines the forum and the remedy: an ultra vires or procedural challenge is a state-law action for invalidation, whereas a takings or First Amendment claim opens a federal remedy in damages. Second, the record made before the board is generally the record on review; the challenge is usually won or lost in the administrative hearing, not in court.

Three systems govern the use of land in relation to neighbours, and the mature practitioner treats them as a single field with three instruments rather than as three separate subjects. Chapter 23 developed the private system of covenants and equitable servitudes; Chapter 28 developed the judicial system of nuisance; this chapter develops the public system of zoning.

The systems are cumulative, not alternative, and their interaction is a recurring source of error. A use permitted by the ordinance may nonetheless be a nuisance, because compliance with public regulation is not a defence (§ 29.20 and Chapter 28). A use permitted by the ordinance may be barred by a recorded covenant, and the covenant is enforceable notwithstanding the ordinance. A use forbidden by the ordinance is not made lawful by the neighbours' consent or by the release of a covenant. The correct order of inquiry for any proposed use is therefore: the instrument, then the ordinance, then the general law of nuisance.

The illustrations that follow apply the chapter's doctrine on the pattern used throughout this volume: identify the interests, name the doctrine, state the baseline, note any statutory overlay, state the result, and qualify it.

The following propositions are commonly asserted and are wrong. Each is stated as the error, followed by the correction.

1. “Zoning is a taking of property.” Zoning is an exercise of the police power and requires no compensation unless it goes too far under the doctrines of Chapter 30. Diminution in value, even substantial diminution, does not itself establish a taking.
2. “A municipality has an inherent power to zone.” It has only the authority the State delegates. An ordinance beyond the enabling act is void without regard to its merits.
3. “Euclid settled that zoning ordinances are constitutional.” Euclid sustained comprehensive districting in general terms and expressly reserved as-applied challenges; Nectow sustained one two years later.
4. “If the ordinance permits the use, it cannot be a nuisance.” Compliance with zoning is a floor, not a ceiling. Only an express legislative authorization of the very activity in the very manner conducted supplies the defence, and generally only as to injunctive relief.
5. “If a covenant permits the use, zoning cannot forbid it, and vice versa.” Private and public controls are cumulative. The more restrictive governs, and neither displaces the other.
6. “A nonconforming use is unlawful and may be shut down.” It is lawful and may continue; only its expansion, change, resumption after abandonment, and reconstruction are restricted, and termination requires amortization where that is permitted.
7. “The right to a nonconforming use belongs to the owner and ends on sale.” It attaches to the land and passes with it.
8. “A variance is available whenever the ordinance prevents the most profitable use.” Lost profit is not unnecessary hardship. The standard is the absence of any reasonable return, from conditions inhering in the land.
9. “Purchasing with knowledge of the restriction always defeats a variance.” The majority rule is that knowledge is not itself a bar; the bar is hardship the applicant created, and knowledge is evidence bearing on that question.
10. “A special exception is a favour the board may withhold.” The legislature has already approved the use for the district; the board verifies compliance with the ordinance's standards, and neighbourhood opposition unrelated to those standards is not a lawful ground of denial.
11. “Spot zoning means rezoning a small parcel.” Size is a factor only. The vice is a classification inconsistent with the plan and the surroundings conferring a particular benefit on a single owner.
12. “Municipalities may contract to rezone in exchange for developer commitments.” Contract zoning binding the legislative body is generally invalid; conditional zoning and, where authorized by statute, development agreements are the lawful routes.
13. “A developer who has spent heavily on plans is protected from a zoning change.” Under the majority rule nothing vests without a lawfully issued permit and substantial construction or obligation in reliance.
14. “Aesthetic objectives cannot support zoning.” They can, in the great majority of States. The live question is whether the standards are ascertainable enough to survive vagueness and delegation attack.
15. “A town may exclude adult businesses because they are offensive.” It may regulate their location for secondary effects while leaving reasonable alternative avenues of communication; it may not exclude them because of the content of the expression.
16. “Churches can be zoned like any other use.” RLUIPA imposes equal-terms, nondiscrimination, unreasonable-limitation, and substantial-burden constraints that have no analogue for secular uses.
17. “A municipality owes no duty to consider housing needs beyond its borders.” In New Jersey and, in varying degrees, in a number of other States, the delegated police power must be exercised for the general welfare of the region; and the Fair Housing Act operates everywhere.
18. “A zoning decision may be challenged whenever the owner chooses.” Short statutory limitations periods, exhaustion, and ripeness requirements bar most late challenges, and the administrative record ordinarily fixes the evidence on review.

Zoning is the legislative generalization of the law of nuisance. It rests on the police power, an inherent attribute of state sovereignty that municipalities exercise only by delegation, and it requires no compensation because it regulates rather than appropriates. The Standard State Zoning Enabling Act supplied the structure — districts, uniformity, a comprehensive plan requirement, a board of adjustment, and notice-and-hearing procedure — that the American ordinance retains a century later.

Euclid sustained comprehensive districting against substantive due process attack, reasoning from the nuisance analogy and prescribing the deferential standard that still governs; Nectow confirmed that the general validity of an ordinance does not immunize its application to a particular parcel. The ordinance regulates along two axes, use and bulk, and modern practice has abandoned the cumulative pyramid for exclusive districting.

Because districting is rigid, the system depends on relief and flexibility devices: the nonconforming use with its restrictions and, in most States, its amortization; the variance, granted for hardship inhering in the land and not for lost profit; the special exception, which verifies compliance with standards the legislature has already approved; amendment, policed by the spot zoning doctrine and, in reform States, by quasi-judicial procedure; conditional zoning and development agreements; and floating zones, PUDs, cluster and overlay districts, incentive zoning, and transferable development rights.

The zoning power is bounded. Vested rights protect the developer who has built under a lawful permit; the First Amendment constrains sign and adult-use regulation; RLUIPA constrains the treatment of religious assemblies; the Fair Housing Act and, in some States, a constitutional general-welfare doctrine constrain exclusion; substantive due process protects the extended family; and state preemption and intergovernmental immunity remove subjects and actors from local control. Chapter 30 takes up the remaining limit, and the most important: the point at which regulation goes so far that the Constitution requires compensation.

• Chapter 21 — Easements (private allocation of use rights).
• Chapter 23 — Real Covenants and Equitable Servitudes (private land use controls).
• Chapter 24 — Common-Interest Communities (private government of land use).
• Chapter 28 — Nuisance (judicial regulation of conflicting uses).
• Chapter 30 — Regulatory Takings (the constitutional limit on the police power).
• Daniel R. Mandelker, Land Use Law (6th ed.), chs. 3–9.
• Richard F. Babcock, The Zoning Game (1966), chs. 1–3.
• Charles M. Haar, In Accordance with a Comprehensive Plan, 68 Harv. L. Rev. 1154 (1955).