[588]*588Opinion
TOBRINER, J.
We face today the question of the validity of an initiative ordinance enacted by the voters of the City of Livermore which prohibits issuance of further residential building permits until local educational, sewage disposal, and water supply facilities comply with specified standards.1 Plaintiff, an association of contractors, subdividers, and other persons interested in residential construction in Livermore, brought this suit to enjoin enforcement of the ordinance. The superior court issued a permanent injunction, and the city appealed.
In Hurst v. City of Burlingame (1929) 207 Cal. 134 [277 P. 308], we held that statutes requiring notice and hearing to precede enactment of municipal zoning and land use ordinances applied to initiatives, a holding which effectively denied voters of general law cities the power to enact such legislation by initiative. In accord with that precedent, the trial court here held that Livermore, as a general law city, lacked authority to enact the initiative ordinance at issue. We have concluded, however, that Hurst was incorrectly decided; the statutory notice and hearing provisions govern only ordinances enacted by city council action and do not limit the power of municipal electors, reserved to them by the state Constitution, to enact legislation by initiative. We therefore reverse the trial court holding on this issue.
We also reject the trial court’s alternative holding that the ordinance is unconstitutionally vague. By interpreting the ordinance to incorporate standards established by the Livermore Valley Joint School District and the Regional Water Quality Control Board, we render its terms sufficiently specific to comply with constitutional requisites. The failure of the ordinance to designate the person or agency who determines when its standards have been fulfilled does not make it unconstitutionally vague; the duty to enforce the ordinance reposes in the city’s building inspector, whose decisions are subject to judicial review by writ of mandamus.
Finally, we reject plaintiff’s suggestion that we sustain the trial court’s injunction on the ground that the ordinance unconstitutionally attempts [589]*589to bar immigration to Livermore. Plaintiff’s contention symbolizes the growing conflict between the efforts of suburban communities to check disorderly development, with its concomitant problems of air and water pollution and inadequate public facilities, and the increasing public need for adequate housing opportunities. We take this opportunity, therefore, to reaffirm and clarify the principles which govern validity of land use ordinances which substantially limit immigration into a community; we hold that such ordinances need not be sustained by a compelling state interest, but are constitutional if they are reasonably related to the welfare of the region affected by the ordinance. Since on the limited record before us plaintiff has not demonstrated that the Livermore ordinance lacks a reasonable relationship to the regional welfare, we cannot hold the ordinance unconstitutional under this standard.
1. Summary of proceedings.
The initiative ordinance in question was enacted by a majority of the voters at the Livermore municipal election of April 11, 1972, and became effective on April 28, 1972. The ordinance, set out in full in the margin,2 [590]*590states that it was enacted to further the health, safety, and welfare of the citizens of Livermore and to contribute to the solution of air pollution. Finding that excessive issuance of residential building permits has caused school overcrowding, sewage pollution, and water rationing, the ordinance prohibits issuance of further permits until three standards are met: “1. Educational Facilities—No double sessions in the schools nor overcrowded classrooms as determined by the California Education Code. 2. Sewage—The sewage treatment facilities and capacities meet the standards set by the Regional Water Quality Control Board. 3. Water Supply—No rationing of water with respect to human consumption or irrigation and adequate water reserves for fire protection exist.”
Plaintiff association filed suit to enjoin enforcement of the ordinance and for declaratoiy relief. After the city filed its answer, all parties moved for judgment on the pleadings and stipulated that the court, upon the pleadings and other documents submitted, could determine the merits of the cause. On the basis of that stipulation the court rendered findings and entered judgment for plaintiff. The city appeals from that judgment.
2. The enactment of the Livermore ordinance by initiative does not violate the state zoning law.
The superior court found that the initiative ordinance was adopted “without complying with the statutes . . . governing general law cities,” specifically Government Code sections 65853 through 65857. These sections provide that any ordinance which changes zoning ór imposes a land use restriction listed in Government Code section 65850 can be enacted only after noticed hearing before the city’s planning commission and legislative body.3 The superior court concluded that notice and [591]*591hearing must precede enactment of any ordinance regulating land use. Since Livermore passed its ordinance pursuant to the procedures specified in the statutes governing municipal initiatives (Elec. Code, § 4000 et seq.), which do not provide for hearings before the city planning commission or council, the court held the ordinance invalid.
The amendment of the California Constitution in 1911 to provide for the initiative and referendum signifies one of the outstanding achievements of the progressive movement of the early 1900’s.4 Drafted in light of the theory that all power of government ultimately resides in the people, the amendment speaks of the initiative and referendum, not as a right granted the people, but as a power reserved by them.5 Declaring it “the duty of the courts to 'jealously guard this right of the people” (Martin v. Smith (1959) 176 Cal.App.2d 115, 117 [1 Cal.Rptr. 307]), the courts have described the initiative and referendum as articulating “one of the most precious rights of our democratic process” (Mervynne v. Acker, supra, 189 Cal.App.2d 558, 563). “[I]t has long been our judicial policy to apply a liberal construction to this power wherever it is challenged in order that the right be not improperly annulled. If doubts can reasonably be resolved in favor of the use of this reserve power, courts will preserve it.” (Mervynne v. Acker, supra, 189 Cal.App.2d 558, 563-564; Gayle v. Hamm, supra, 25 Cal.App.3d 250, 258.)6
The 1911 amendment, in reserving the right of initiative to electors of counties and cities, authorized the Legislature to establish procedures to facilitate the exercise of that right.7 Accordingly the Legislature enacted [592]*592statutes, now codified as sections 4000-4023 of the Election Code, providing for the circulation of petitions, the calling of elections, and other procedures required to enact an initiative measure.
The 1911 amendment was first applied to zoning matters in 1927 in Dwyer v. City Council, supra, 200 Cal. 505, in which the court mandated the Berkeley City Council to submit a zoning ordinance to referendum. The opinion reasoned that since the city council had the legislative authority to enact zoning ordinances, the people had the power to do so by initiative or referendum. Rejecting an argument that the referendum procedure denied affected persons the right, granted them by municipal ordinance, to appear before the city council and state their views on the ordinance, the court replied that “the matter has been removed from the forum of the Council to the forum of the electorate. The proponents and opponents are given all the privileges and rights to express themselves in an open election that a democracy or republican form of government can afford to its citizens. ... It is clear that the constitutional right reserved by the people to submit legislative questions to a direct vote cannot be abridged by any procedural requirement....” (200 Cal. at p. 516.)
Two years later the court decided Hurst v. City of Burlingame, supra, 207 Cal. 134, the decision on which the trial court in the instant case based its ruling. The City of Burlingame had enacted by initiative a city-wide zoning ordinance which classified as residential the property where plaintiff had a retail store. Contending that he had been denied the right to a public hearing established in the Zoning Act of 1917 (Stats. 1917, ch. 734, p. 1419), plaintiff sued to enjoin enforcement of the ordinance. Beginning with the premise that “an ordinance proposed by the electors of a county or of a city in this state under the initiative law must constitute such legislation as the legislative body of such county or city has the power to enact . . . .” (207 Cal. at p. 140), the Hurst court reasoned that since the board of trustees of the City of Burlingame could not lawfully enact a zoning ordinance without complying with the hearing requirement of the state law, the voters could not adopt such an ordinance by initiative.
[593]*593Responding to the argument that the enactment of the ordinance complied with the state initiative law, the court stated that “The initiative law and the zoning law are hopelessly inconsistent and in conflict as to the manner of the preparation and adoption of a zoning ordinance. The Zoning Act is a special statute dealing with a particular subject and must be deemed to be controlling over the initiative, which is general in its scope.” (P. 141.) Finally, the court distinguished Dwyer v. City Council, supra, 200 Cal. 505, on the ground that Dwyer upheld a referendum, and thus persons affected by the referendum had already been granted a right to notice and hearing' at the time of the original enactment of the ordinance. (See p. 142.)
Although Hurst thus held the Burlingame initiative invalid for noncompliance with the state zoning law, the court added a constitutional dictum, asserting that “the statutory notice and hearing . . . becomes necessary in order to satisfy the requirements of due process. . . .” (P. 141.) In later years this constitutional dictum overshadowed the statutory holding of Hurst. Courts and commentators alike questioned Hurst’s statutory holding,8 but reexamination of that holding seemed pointless if the landowner’s right to notice and hearing derived from constitutional compulsion independent of statute.9
Two years ago, however, in San Diego Bldg. Contractors Assn. v. City Council (1974) 13 Cal.3d 205, 216 [118 Cal.Rptr. 146, 529 P.2d 570, 72 A.L.R.3d 973] (app. dism. (1976) 427 U.S. 901 [49 L.Ed.2d 1195, 96 S.Ct. 3184]) we expressly disapproved the constitutional dictum of Hurst and later decisions. We held that a city violates no constitutional prohibition in enacting a zoning ordinance without notice and hearing to landowners, and hence may do so by initiative. (13 Cal.3d at pp. 217-218.) That decision clears the way for a long-needed reconsideration of the actual holding of Hurst that bars a general law city from enacting a zoning ordinance by initiative.
At first glance it becomes apparent that something must be wrong with the reasoning in Hurst. Starting from a premise of equálity—that the voters possess only the same legislative authority as does the city [594]*594council—Hurst arrived at the conclusion that only the council and not the voters had the authority to enact zoning measures. Thus in the name of equality Hurst decrees inequality. The errors which lead to this non sequitur appear after further analysis.
First, Hurst, erroneously contriving a conflict between state zoning statutes and the initiative law, set out to resolve that presumed conflict.10 No conflict occurs, however; the Legislature never intended the notice and hearing requirements of the zoning law to apply to the enactment of zoning initiatives. (See Comment, The Initiative and Referendum’s Use in Zoning (1976) 64 Cal.L.Rev. 74, 104-105.) The Legislature plainly drafted the questioned provisions of the zoning law with a view to ordinances adopted by vote of the city council; the provisions merely add certain additional procedural requirements to those already specified in Government Code sections 36931-36939 for the enactment of ordinances in general. Procedural requirements which govern council action, however, generally do not apply to initiatives,11 any more than the provisions of the initiative law govern the enactment of ordinances in council. No one would contend, for example, that an initiative of the people failed because a quorum of councilmen had not voted upon it, any more than one would contend that an ordinary ordinance of a council failed because a majority of voters had not voted upon it.
In the second place, Hurst, in treating the case as one involving a conflict between two statutes of equal status—the zoning law and the initiative law—overlooked a crucial distinction: that although the procedures for exercise of the right of initiative are spelled out in the [595]*595initiative law, the right itself is guaranteed by the Constitution. The 1911 constitutional amendment, in reserving the right of initiative on behalf of municipal voters, stated that “This section is self-executing, but legislation may be enacted to facilitate its operation, but in no way limiting or restricting either the provisions of this section or the powers herein reserved(Former Cal. Const., art. IV, § 1.) (Italics added.)12 Although the Legislature can specify the manner in which general law cities enact ordinances restricting land use,13 legislation which permits council action but effectively bars initiative action may run afoul of the 1911 amendment. (See Comment, op. cit., supra, 64 Cal.L.Rev. 74, 102.) Thus the notice and hearing provisions of the state zoning law, if interpreted to bar initiative land use ordinances, would be of doubtful constitutionality.; all such doubt dissolves in the light of an interpretation which limits those requirements to ordinances enacted by city councils.
The fact that the zoning law is a special statute will not support Hurst; special legislation is still subject to constitutional limitations. If, for example, a “special” statute were enacted prohibiting criticism of a named official, such as the Vice-President, it would not be deemed controlling over the First Amendment on the ground that the latter is “general in its scope.” Indeed if the constitutional power reserved by the people can be abridged by special statutes, then by enacting a host of special statutes the Legislature could totally abrogate that power.
Finally, Hurst erred in distinguishing Dwyer v. City Council, supra, 200 Cal. 505, on the ground that Dwyer involved a referendum on a zoning ordinance; as Dwyer itself pointed out, “if the right of referendum can be invoked, the corollary right to initiate legislation must be conceded to exist.” (200 Cal. at p. 511.)
[596]*596Thus both precedent and established principles of judicial construction dictate the conclusion that Hurst erred in holding the notice and hearing provisions of the Zoning Act of 1917 applied to zoning ordinances enacted by initiative. Resting upon the precepts that statutes which are apparently in conflict should, if reasonably possible, be reconciled (see, e.g., Warne v. Harkness (1963) 60 Cal.2d 579, 588 [35 Cal.Rptr. 601, 387 P.2d 377]; Pacific Motor Transport Co. v. State Bd. of Equalization (1972) 28 Cal.App.3d 230, 235 [104 Cal.Rptr. 558]); that a statute should be construed to “eliminate . . . doubts as to the provision’s constitutionality” (In re Kay (1970) 1 Cal.3d 930, 942 [83 Cal.Rptr. 686, 464 P.2d 142]); that the initiative power must be broadly construed, resolving all doubts in favor of the reserved power (see cases cited pp. 591-592, ante, and fn. 6), we resolve that Hurst v. Burlingame, supra, 207 Cal. 134, was incorrectly decided and is therefore overruled.14
The notice and hearing provisions of the present zoning law (Gov. Code, §§ 65853-65857), like the provisions of the 1911 law before the Hurst court, make no mention of zoning by initiative. The procedures they prescribe refer only to action by the city council, and are inconsistent with the regulations that the Legislature has established to govern enactment of initiatives. For the reasons stated in our discussion of Hurst v. Burlingame, supra, we conclude that sections 65853-65857 do not apply to initiative action, and that the Livermore ordinance is not invalid for noncompliance with those sections.
3. The Livermore ordinance is not voidfor vagueness.
The trial court found the ordinance unconstitutionally vague on two grounds: (1) that the ordinance did not contain sufficiently specific [597]*597standards for the issuance or denial of building permits, and (2) that it did not specify what person or agency was empowered to determine if the ordinance’s standards have been met. W,e disagree with both rationales and find the ordinance sufficiently specific to fulfill constitutional requirements.
The controversy concerning the specificity of the ordinance centers upon the standard as to education. The ordinance prohibits issuance of residential building permits until a “satisfactory solution” has been evolved to the problem of “Educational Facilities;” it. defines a satisfactory solution as one characterized by “No double sessions in the schools nor overcrowded classrooms as determined by the California Education Code.”
The term “double sessions” is sufficiently specific; as stated by Professor Deutsch, it “can be defined by reference to common practice, since the term is frequently used to refer to a situation where different groups of students in the same grade are attending the same, school at different times of the day because of a lack of space.” (Deutsch, op. cit., supra, pp. 22-23.) The phrase “overcrowded classrooms as determined by the California Education Code,” however, is less clear, since nowhere in the Education Code does there appear a definition of “overcrowded classrooms.”
The City of Livermore, however, points out that the ordinance does not refer to a definition of “overcrowded classrooms” contained in the Education Code, but to a determination of that subject. The language, it contends—and plaintiff does not dispute the contention—was intended to refer to resolution 3220, adopted by the board of the Livermore Valley Joint School District on January 18, 1972, in which that board, pursuant to authority granted it by Education Code section 1052, established clear and specific standards for determining whether schools are overcrowded.15
[598]*598Rather than interpret the ordinance in a manner which would expose it to the charge of unconstitutional vagueness, we adopt the suggestion of the city and construe the ordinance’s standard on education to incorporate the specific guidelines established in board resolution 3220. In so doing we conform to the rule that enactments should be interpreted when possible to uphold their validity (see San Francisco Unified School Dist. v. Johnson (1971) 3 Cal.3d 937, 948 [92 Cal.Rptr. 309, 479 P.2d 669]), and the corollary principle that courts should construe enactments to give specific content to terms that might otherwise be unconstitutionally vague. (See Bloom v. Municipal Court (1976) 16 Cal.3d 71 [127 Cal.Rptr. 317, 545 P.2d 229]; In re Kay, supra, 1 Cal.3d 930.)
Our decision in Braxton v. Municipal Court (1973) 10 Cal.3d 138 [109 Cal.Rptr. 897, 514 P.2d 697], illustrates the principle and provides a close analogy to the present case. In Braxton, we construed Penal Code section 626.4, which authorized a state college or university to bar from its campus anyone who had “disrupted” the orderly operation of the campus. Defendants argued that the term “disrupted” was unconstitutionally vague. We determined, however, that the Legislature had intended to authorize banishment only of persons who had violated other more specific criminal statutes. Although section 626.4 did not expressly refer to such other statutes, we interpreted section 626.4 to incorporate the specific standards set out in those statutes in order to uphold the constitutionality of the section. (10 Cal.3d at p. 152.)
Following the course suggested by Braxton, we construe the Livermore ordinance to incorporate the standards for determining the [599]*599overcrowded condition of schools contained in the school board resolution of January 18, 1972. So construed, the ordinance provides a clear and ascertainable educational standard to guide the issuance or denial of a building permit, and is not void for vagueness.
The ordinance’s standards relating to sewage and water supply present no constitutional difficulties. The sewage provision incorporates the “standards set by the Regional Water Quality Control Board;” that agency has in fact established specific and detailed standards of water purification and sewage disposal.16 The water supply provision describes a “satisfactory solution” as one in which water is not rationed, and “adequate water reserves for fire protection exist.” The existence of rationing is an objective fact which can be ascertained by inquiry to the agencies having authority to ration.17 Although individuals may differ as to the adequacy of reserves for fire protection, the considered judgment of the agencies responsible for fire protection would provide a reliable guide.
Although we háve determined that the ordinance’s standards meet constitutional requirements of certainty, plaintiff argues, and the trial court held, that the ordinance is void because it fails to designate what agency or person determines whether these standards have been achieved. We question plaintiff’s underlying assumption that an ordinance or statute is void if it does not specify on its face the agency that is to adjudge disputes concerning its application; by such a test most of the civil and criminal laws of this state would be invalidated. In any event, we believe that the Livermore ordinance, read in the light of the structure of Livermore’s city government and the applicable judicial decisions, does indicate the method by which disagreements concerning the ordinance’s standards are resolved.
The Livermore ordinance establishes standards to govern the issuance or denial of residential building permits. These standards must be [600]*600directed in the first instance to the city building inspector, the official charged with the duty of issuing or denying such permits. Since the duties of this official are ministerial in character, his decisions can be reviewed by writ of mandamus. (McCombs v. Larson (1959) 176 Cal.App.2d 105, 107 [1 Cal.Rptr., 140]; Palmer v. Fox (1953) 118 Cal.App.2d 453 [258 P.2d 30].) Thus the ultimate decision as to compliance with the standards will be rendered by the courts. (See generally Hagman et al., Cal. Zoning Practice (Cont.Ed.Bar 1969) § 12.4.)
4. On the limited record before us, plaintiff cannot demonstrate that the Livermore ordinance is riot a constitutional exercise of the city’s police power.
Plaintiff urges that we affirm the trial court’s injunction on a ground which it raised below, but upon which the trial court did not rely. Plaintiff contends that the ordinance proposes, and will cause, the prevention of nonresidents from migrating to Livermore, and that the ordinance therefore attempts an unconstitutional exercise of the police power, both because no compelling state interest justifies its infringement upon the migrant’s constitutionally protected right to travel, and because it exceeds the police power of the municipality.18
The ordinance on its face imposes no absolute prohibition or limitation upon population -growth or residential construction. It does provide that no building permits will issue unless standards for educational facilities, water supply and sewage disposal have been met, but plaintiff presented no evidence to show that the ordinance’s standards were unreasonable or unrelated to their apparent objectives of protecting the public health and welfare. Thus, we do not here confront the question of the constitutionality of an ordinance which limits or bars population growth either directly in express language or indirectly by the imposition of prohibitory standards; we adjudicate only the validity of [601]*601an ordinance limiting building permits in accord with standards that reasonably measure the adequacy of public services.
As we shall explain, the limited record here prevents us from resolving that constitutional issue. We deal here with a case in which a land use ordinance is challenged solely on the ground that it assertedly exceeds the municipality’s authority under the police power; the challenger eschews any claim that the ordinance discriminates on a basis of race or wealth. Under such circumstances, we view the past decisions of this court and the federal courts as establishing the following standard: the land use restriction withstands constitutional attack if it is fairly debatable that the restriction in fact bears a reasonable relation to the general welfare. For the guidance of the trial court we point out that if a restriction significantly affects residents of surrounding communities, the constitutionality of the restriction must be measured by its impact not only upon the welfare of the enacting community, but upon the welfare of the surrounding region. We explain the process by which the court can determine whether or not such a restriction reasonably relates to the regional welfare. Since the record in the present case is limited to the pleadings and stipulations, and is devoid of evidence concerning the probable impact and duration of the ordinance’s restrictions, we conclude that we cannot now adjudicate the constitutionality of the ordinance. Thus we cannot sustain the trial court judgment on the ground that the ordinance exceeds the city’s authority under the police power; that issue can be resolved only after trial.
We turn now to consider plaintiff’s arguments in greater detail. Seeking to capitalize upon the absence of an evidentiary record, plaintiff contends that the challenged ordinance must be subjected to strict judicial scrutiny; that it can be sustained only upon a showing of a compelling interest, and that the city has failed to make that showing.
Many writers have contended that exclusionary land use ordinances tend primarily to exclude racial minorities and the poor, and on that account should be subject to strict judicial scrutiny. (See, e.g., Davidoff & Davidoff, Opening the Suburbs: Toward Inclusionary Land Use Controls (1971) 22 Syracuse L.Rev. 509; Sager, Tight Little Islands: Exclusionary Zoning, Equal Protection, and the Indigent (1969) 21 Stan.L.Rev. 767; Note, Phased Zoning: Regulation of the Tempo and Sequence of Land Development, 26 Stan.L.Rev. 585, 597, fn. 45 and authorities there cited; [602]*602Note, The Equal Protection Clause and Exclusionary Zoning after Valtierra and Dandridge (1971) 81 Yale L.J. 61.) These writers, however, are concerned primarily with ordinances which ban or limit less expensive forms of housing while permitting expensive single family residences on large lots. The Livermore ordinance is not made from this mold; it impartially bans all residential construction, expensive or inexpensive. Consequently plaintiff at bar has eschewed reliance upon any claim that the ordinance discriminates on a basis of race or wealth.
Plaintiff’s contention that the Livermore ordinance must be tested by a standard of strict scrutiny, and can be sustained only upon a showing of a compelling state interest, thus rests solely on plaintiff’s assertion that the ordinance abridges a constitutionally protected right to travel. As we shall explain, however, the indirect burden imposed on the right to travel by the ordinance does not warrant application of the plaintiff’s asserted standard of “compelling interest.”19
In asserting that legislation which burdens a right to travel requires strict scrutiny, and can be sustained only upon proof of compelling need, plaintiff relies on recent decisions of this court (In re King (1970) 3 Cal.3d 226 [90 Cal.Rptr. 15, 474 P.2d 983]) and the United States Supreme Court (Memorial Hospital v. Maricopa County (1974) 415 U.S. 250 [39 L.Ed.2d 306, 94 S.Ct. 1076]; Dunn v. Blumstein (1972) 405 U.S. 330 [31 L.Ed.2d 274, 92 S.Ct. 995]; Shapiro v. Thompson (1969) 394 U.S. 618 [22 L.Ed.2d 600, 89 S.Ct. 1322]). The legislation held invalid by those decisions, however, directly burdened the right to travel by distinguishing between nonresidents or newly arrived residents on the one hand and established residents on the other, and imposing penalties or disabilities on the former group.20
Both the United States Supreme Court and this court have refused to apply the strict constitutional test to legislation, such as the present [603]*603ordinance, which does not penalize travel and resettlement but merely makes it more difficult for the outsider to establish his residence in the place of his choosing.21 (See Village of Belle Terre v. Boraas (1973) 416 U.S. 1, 7 [39 L.Ed.2d 797, 803, 94 S.Ct. 1536]; Ector v. City of Torrance (1973) 10 Cal.3d 129, 135 [109 Cal.Rptr. 849, 514 P.2d 433]; see also McCarthy v. Philadelphia Civil Serv. Comm’n (1976) 424 U.S. 645 [47 L.Ed.2d 366, 96 S.Ct. 1154]; Construction Ind. Ass’n, Sonoma Cty. v. City of Petaluma, supra, 522 F.2d 897, 906-907, fn. 13; Note, 50 N.Y.U.L.F. (1975) 1163, 1168.) The only contrary authority, the decision of the federal district court in Construction Ind. Ass’n, Sonoma Cty. v. City of Petaluma (N.D.Cal. 1974) 375 F.Supp. 574 holding that an ordinance limiting residential construction must be supported by a compelling state interest has now been reversed by the Court of Appeals for the Ninth Circuit. (Construction Ind. Ass’n, Sonoma Cty. v. City of Petaluma, supra, 522 F.2d 897, cert. den., 424 U.S. 934 [47 L.Ed.2d 342, 96 S.Ct. 1148].)
Most zoning and land use ordinances affect population growth and density. (See Construction Ind. Ass’n, Sonoma Cty v. City of Petaluma, supra, 522 F.2d 897, 906; Note, op. cit., supra, 26 Stan.L.Rev. 585, 606-607, fn. 91.) As commentators have observed, to insist that such zoning laws are invalid unless the interests supporting the exclusion are compelling in character, and cannot be achieved by an alternative method, would result in wholesale invalidation of land use controls and endanger the validity of city and regional planning. (See Note, op. cit., supra, 26 Hastings L.J. 849, 854.) “Were a court to . . . hold that an inferred right of any group to live wherever it chooses might not be abridged without some compelling state interest, the law of zoning would be literally turned upside down; presumptions of validity would become presumptions of invalidity and traditional police powers of a state would be severely circumscribed.” (Comment, Zoning, Communes and Equal Protection, 1973 Urban L.Ann. 319, 324.)
We conclude that the indirect burden upon the right to travel imposed by the Livermore ordinance does not call for strict judicial scrutiny. The validity of the challenged ordinance must be measured by the more [604]*604liberal standards that have traditionally tested the validity of land use restrictions enacted under the municipal police power.22
This conclusion brings us to plaintiff’s final contention: that the Livermore ordinance exceeds the authority conferred upon the city under the police power. The constitutional measure by which we judge the validity of a land use ordinance that is assailed as exceeding municipal authority under the police power dates in California from the landmark decision in Miller v. Board of Public Works (1925) 195 Cal. 477 [234 P. 381, 38 A.L.R. 1479]. Upholding a Los Angeles ordinance which excluded commercial and apartment uses from certain residential zones, we declared that an ordinance restricting land use was valid if it had a “real or substantial relation to the public health, safety, mprals or general welfare.” (195 Cal. at p. 490.) A year later the United States Supreme Court, in the landmark case of Euclid v. Ambler Co. (1926) 272 U.S. 365 [71 L.Ed. 303, 47 S.Ct. 114, 54 A.L.R. 1016], adopted the same test, holding that béfore a zoning ordinance can be held unconstitutional, “it must be said . . . that [its] provisions are clearly arbitrary and unreasonable, having no substantial relation to the public health, safety, morals, or general welfare.” (272 U.S. at p. 395 [71 L.Ed. at p. 314].) Later California decisions confirmed that a land use restriction lies within the public power if it has a “reasonable relation to the public welfare.” (Lockard v. City of Los Angeles (1949) 33 Cal.2d 453, 461 [202 P.2d 38, 7 A.L.R.2d 990]; Hamer v. Town of Ross (1963) 59 Cal.2d 776, 783 [31 Cal.Rptr. 335, 382 P.2d 375]; see Town of Los Altos Hills v. Adobe Creek Properties, Inc., supra, 32 Cal.App.3d 488, 508-509 and cases there cited.)
In deciding whether a challenged ordinance reasonably relates to the public welfare, the courts recognize that such ordinances are presumed [605]*605to be constitutional, and come before the court with every intendment in their favor. (Lockard v. City of Los Angeles, supra, 33 Cal.2d 453, 460.) “The courts may differ with the zoning authorities as to the ‘necessity or propriety of an enactment,’ but so long as it remains a ‘question upon which reasonable minds might differ,’ there will be no judicial interference with the municipality’s determination of policy.” (Clemons v. City of Los Angeles (1950) 36 Cal.2d 95, 98 [222 P.2d 439].) In short, as stated by the Supreme Court in Euclid v. Ambler Co., supra, “If the validity . . . be fairly debatable, the legislative judgment must be allowed to control.” (272 U.S. 365, 388 [71 L.Ed. 303, 311].)
Recent decisions of the United States Supreme Court and the Court of Appeals for the Ninth Circuit have applied this liberal standard and, deferring to legislative judgment, have upheld ordinances attacked as exclusionary. In Village of Belle Terre v. Boraas, supra, 416 U.S. 1 [39 L.Ed.2d 797], the court sustained an ordinance which banned all multiple family housing. The majority opinion by Justice Douglas found a rational basis for the ordinance in the community’s desire to preserve a pleasant environment; “[t]he police power,” he asserted, “is not confined to the elimination of filth, stench, and unhealthy places. It is ample to lay out zones where family values, youth values, and the blessings of quiet seclusion and clean air make the area a sanctuary for people.” (416 U.S. at p. 9 [39 L.Ed.2d at p. 804].) In dissent, Justice Marshall argued that the village’s exclusion of groups of three or more unrelated persons from living in a single residence violated protected rights of privacy and association. He agreed, however, that the village could properly enact ordinances to control population density and restrict uncontrolled growth so long as it did not abridge fundamental rights, and that in reviewing such ordinances the courts should defer to the legislative judgment. (See 416 U.S. at pp. 13, 19-20 [39 L.Ed.2d at pp. 806, 810-811].)
In Construction Ind. Ass’n, Sonoma Cty. v. City of Petaluma, supra, 522 F.2d 897, the Ninth Circuit Court of Appeals upheld a city ordinance fixing a housing development growth rate of 500 units per year. Relying largely on Belle Terre v. Boraas, supra, 416 U.S. 1 [39 L.Ed.2d 797], the court concluded that “the concept of public welfare is sufficiently broad [606]*606to uphold Petaluma’s desire to preserve its small town character, its open space and low density of population, and to grow at an orderly and deliberate pace.” (522 F.2d at pp. 908-909.) The Supreme Court denied certiorari. (424 U.S. 934 [47 L.Ed.2d 342, 96 S.Ct. 1148].)
We conclude from these federal decisions that when an exclusionary ordinance is challenged under the federal due process clause, the standard of constitutional adjudication remains that set forth in Euclid v. Ambler Co., supra, 272 U.S. 365 [71 L.Ed. 303]: if it is fairly debatable that the ordinance is reasonably related to the public welfare, the ordinance is constitutional. A number of recent decisions from courts of other states, however, have declined to accord the traditional deference to legislative judgment in the review of exclusionaiy ordinances, and ruled that communities lacked authority to adopt such ordinances. Plaintiff urges that we apply the standards of review employed in those decisions in passing upon the instant ordinance.
The cases cited by plaintiff, however, cannot serve as a guide to resolution of the present controversy. Not only do those decisions rest, for the most part, upon principles of state law inapplicable in California, but, unlike the present case, all involve ordinances which impede the ability of low or moderate income persons to immigrate to a community but permit largely unimpeded entry by wealthier persons.23
[607]*607We therefore reaffirm the established constitutional principle that a local land use ordinance falls within the authority of the police power if it is reasonably related to the public welfare. Most previous decisions applying this test, however, have involved ordinances without substantial effect beyond the municipal boundaries. The present ordinance, in contrast, significantly affects the interests of nonresidents who are not represented in the city legislative body and cannot vote on a city initiative. We therefore believe it desirable for the guidance of the trial court to clarify the application of the traditional police power test to an ordinance which significantly affects nonresidents of the municipality.
When we inquire whether an ordinance reasonably relates to the public welfare, inquiiy should begin by asking whose welfare must the ordinance serve. In past cases, when discussing ordinances without significant effect beyond the municipal boundaries, we have been content to assume that the ordinance need only reasonably relate to the welfare of the enacting municipality and its residents. But municipalities are not isolated, islands remote from the needs and problems of the area in which they are located; thus an ordinance, superficially reasonable from the limited viewpoint of the municipality, may be disclosed as unreasonable when viewed from a larger perspective.
These considerations impel us to the conclusion that the proper constitutional test is one which inquires whether the ordinance reasonably relates to the welfare of those whom it significantly affects. If its impact is limited to the city boundaries, the inquiiy may be limited accordingly; if, as alleged here, the ordinance may strongly influence the supply and distribution of housing for an entire metropolitan region, judicial inquiiy must consider the welfare of that region.24
As far back as Euclid v. Ambler Co., courts recognized “the possibility of cases where the general public interest would so far outweigh the „ interest of the municipality that the municipality would not be allowed to stand in the way.” (272 U.S. 365, 390 [71 L.Ed. 303, 311].) More recently, in Scott v. City of Indian Wells (1972) 6 Cal.3d 541 [99 Cal.Rptr. [608]*608745, 492 P.2d 1137], we stated that “To hold . . . that defendant city may zone the land within its border without any concern for [nonresidents] would indeed ‘make a fetish out. of invisible municipal boundary lines and a mockery of the principles of zoning.’ ” (P. 548.) The New Jersey Supreme Court summed up the principle and explained its doctrinal basis: “[I]t is fundamental and not to be forgotten that the zoning power is a police power of the state and the local authority is acting only as a delegate of that power and is restricted in the same manner as is the state. So, when regulation does have a substantial external impact, the welfare of the state’s citizens beyond the borders of the particular municipality cannot be disregarded and must be recognized and served.” (So. Burlington Cty. N.A.A.C.P. v. Tp. of Mt. Laurel, supra, 336 A.2d 713, 726.)25
We explain the process by which a trial court may determine whether a challenged restriction reasonably relates to the regional welfare. The first step in that analysis is to forecast the probable effect and duration of the restriction. In the instant case the Liver-more ordinance posits a total ban on residential construction, but one which terminates as soon as public facilities reach specified standards. Thus to evaluate the impact of the restriction, the court must ascertain the extent to which public facilities currently fall short of the specified standards, must inquire whether the city or appropriate regional agencies have undertaken to construct needed improvements, and must determine when the improvements are likely to be completed.
The second step is to identify the competing interests affected by the restriction. We touch in this area deep social antagonisms. We allude to the conflict between the environmental protectionists and the egalitarian humanists; a collision between the forces that would save the benefits of nature and those that would preserve the opportunity of people in general to settle. Suburban residents who seek to overcome problems of inadequate schools and public facilities to secure “the blessing of quiet seclusion and clean air” and to “make the area a sanctuary for people” (Village of Belle Terre v. Boraas, supra, 416 U.S. 1, [609]*6099 [39 L.Ed.2d 797, 804]) may assert a vital interest in limiting immigration to their community. Outsiders searching for a place to live in the face of a growing shortage of adequate housing, and hoping to share in the perceived benefits of suburban life, may present a countervailing interest opposing barriers to immigration.
Having identified and weighed the competing interests, the final step is to determine whether the ordinance, in light of its probable impact, represents a reasonable acommodation of the competing interests.26 We do not hold that a court in inquiring whether an ordinance reasonably relates to the regional welfare, cannot defer to the judgment of the municipality’s legislative body.27 But judicial deference is not judicial abdication. The ordinance must have a real and substantial relation to the public welfare. (Miller v. Board of Public Works, supra, 195 Cal. 477, 490.) There must be a reasonable basis in fact, not in fancy, to support the legislative determination. (Consolidated Rock Products Co. v. City of Los Angeles (1962) 57 Cal.2d 515, 522 [20 Cal.Rptr. 638, 370 P.2d 342].) Although in many cases it will be “fairly debatable” (Euclid v. Ambler Co., supra, 272 U.S. 365, 388 [71 L.Ed. 303, 311]) that the ordinance reasonably relates to the regional welfare, it cannot be assumed that a land use ordinance can never be invalidated as an enactment in excess of the police power.
The burden rests with the party challenging the constitutionality of an ordinance to present the evidence and documentation which the court will require in undertaking this constitutional analysis. Plaintiff in the present case has not yet attempted to shoulder that burden. [610]*610Although plaintiff obtained a stipulation that as of the date of trial the ordinance’s goals had not been fulfilled, it presented no evidence to show the likely duration or effect of the ordinance’s restriction upon building permits. We must presume that the City of Livermore and appropriate regional agencies will attempt in good faith to provide that community with adequate schools, sewage disposal facilities, and a sufficient water supply; plaintiff, however, has not presented evidence to show whether the city and such agencies have undertaken to construct the needed improvements or when such improvements will be completed. Consequently we cannot determine the impact upon either Livermore or the surrounding region of the ordinance’s restriction on the issuance of building permits pending achievement of its goals.
With respect to the competing interests, plaintiff asserts the existence of an acute housing shortage in the San Francisco Bay Area, but presents no evidence to document that shortage or to relate it to the probable effect of the Livermore ordinance. Defendants maintain that Livermore has severe problems of air pollution and inadequate public facilities which make it reasonable to divert new housing, at least temporarily, to other communities but offer no evidence to support that claim. Without an evidentiaiy record to demonstrate the validity and significance of the asserted interests, we cannot determine whether the instant ordinance attempts a reasonable accommodation of those interests.
In short, we cannot determine on the pleadings and stipulations alone whether this ordinance reasonably relates to the general welfare of the region it affects. The ordinance carries the presumption of constitutionality; plaintiff cannot overcome that presumption on the limited record before us. Thus the judgment rendered on this limited record cannot be sustained on the ground that the initiative ordinance falls beyond the proper scope of the police power.
5. Conclusion.
For the reasons we have explained, the Livermore ordinance is neither invalid on the ground that it was enacted by initiative nor unconstitutional by reason of vagueness. The more difficult question whether the measure is one which reasonably relates to the welfare of the region affected by its exclusionary impact, and thus falls within the police power of the city, cannot be decided on the limited record here. That issue can [611]*611only be resolved by a trial at which evidence is presented to document the probable impact of the ordinance upon the municipality and the surrounding region.
The judgment of the superior court is reversed, and the cause remanded for further proceedings consistent with the views expressed herein.
Wright, C. J., McComb, J., Sullivan, J., and Richardson, J., concurred.