In Associated Home Builders Etc., Inc. v. City of Livermore (1976) 18 Cal.3d 582, the plaintiffs claimed that a City of Livermore ordinance prohibiting the issuance of residential building permits--until such time as local water supply, sewage disposal, and educational facilities complied with specified standards--was an unconstitutional exercise of the city's police power because it unreasonably affected the ability of nonresidents of the city to move into the city. (Id. at pp. 588, 604.) The court first affirmed the long-settled principle that a land use ordinance is a constitutional exercise of the municipality's police power if it is "reasonably related to the public welfare." (Associated Home Builders, supra, 18 Cal.3d at pp. 605-607.) The court then explained that when an ordinance "significantly affects nonresidents of the municipality," the public welfare becomes "the regional welfare" and ordinance must be reasonably related to "the regional welfare." (Id. at pp. 607-608.) "The proper constitutional test . . . inquires whether the ordinance reasonably relates to the welfare of the nonresidents it significantly affects." (Id. at p. 607.) The court explained "the process by which a trial court may determine whether a challenged restriction reasonably relates to the regional welfare. The first step . . . is to forecast the probable effect and duration of the restriction. . . . The second step is to identify the competing interests affected by the restriction. . . . . . . The final step is to determine whether the ordinance, in light of its probable impact, represents a reasonable accommodation of the competing interests." (Associated Home Builders, supra, 18 Cal.3d at pp. 608-609, fn. omitted.) "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." (Id. at p. 609.)