Dеfendant county and its officers appeal from decree enjoining enforcement of those provisions of a comprehensive zoning ordinance which prohibit construction and maintenance of billboards in certain districts.
The ordinanсe was adopted April 18, 1955. It distinguishes between “appurtenant” signs, those which “relate only to goods sold or services rendered upon the building site on *377 which said sign is erected,” and all others, which we shall refer to as off-site signs. Appurtenant signs are permitted in mоst zones but are restricted as to size and number. Off-site signs are permitted only in retail business, general commercial, and industrial zones. Section 12 establishes a “U,” or unclassified district, in which the only restrictions prohibit off-site signs and require a use permit for each оf some 22 uses. The greater part of the county’s unincorporated area is placed in the “U” zone. Enforcement of section 12 against off-site signs was enjoined.
Section 34 provides that nonconforming uses existing at the date of the ordinancе may continue, subject to the usual restrictions against enlargement and against replacement after abandonment or destruction. As to off-site signs, however, the section requires removal by July 1, 1960, from districts in which they are not permitted. Enforcement of this sеction against off-site signs also was enjoined.
The briefs, on both sides, take the all or nothing approach, and in doing so tend to lump together the arguments on sections 12 and 34. There are, however, substantial differences between prospective prohibition and removal of nonconforming uses. For clarity of treatment, and because we have concluded that the judgment must be affirmed in part and reversed in part, we discuss separately the validity of sections 12 and 34.
Section 12 prohibits only new сonstruction of off-site billboards in “U” districts. It does not require removal of any existing sign. Plaintiffs’ argument against it, accepted by the trial court, is that it discriminates arbitrarily against off-site boards in “U” districts, since such boards are the only flatly prohibited use in such areas. The quеstion is whether the regulation reasonably tends to promote the public health, safety, morals or general welfare.
Whether the regulation is arbitrary or unreasonable must be determined under the established rules governing judicial review of exercises of the police power. That power is elastic, and capable of expansion to meet existing conditions of modern life
(Consolidated Rock Products Co.
v.
City of Los Angeles,
Preliminarily, we note that plaintiffs do not attack the prohibition by this ordinance of off-site billboards in residential, agricultural, and similar districts, thus impliedly conceding some basis for distinсtion between such signs and the many uses permitted in such districts. The concession is required. As long ago as 1916, the United States Supreme Court recognized that there is no constitutional bar to “putting billboards, as distinguished from buildings and fences, in a class by themselves ’’
(Cusack
v.
City of Chicago,
Cost of site preparation, construction, and maintenance will restrict development of specific uses until demand makes the projects economically feasible. Meantime, thе obnoxious uses are limited by the requirement of use permits. Billboards, which may be constructed quickly and at comparatively little cost, are not subject to the economic restrictions inherent in the more permanent development of a trеnd toward specific use, There is evidence that installation of billboards in rural *379 areas tends to restrict development for both residential and agricultural uses.
The supervisors may also have felt that billboards are considered unattractive by tourists gеnerally, and that thus their unrestricted proliferation would adversely affect the substantial tourist industry of Monterey County. We recognize that esthetic considerations alone cannot justify a zoning regulation
(Varney & Green
v.
Williams,
Plaintiffs argue, however, that the ordinance is not generаl or uniform, but makes an arbitrary classification in its attempt to distinguish between on-site and off-site signs. The decision principally relied upon by plaintiffs
(City of Santa Barbara
v.
Modern Neon Sign Co.,
It is true that signs “relating only to goods sold or services rendered upon the building site on which . . . erected or maintained, ’ ’ as permitted by the ordinance, may, although strictly limited as to size and number, have much the same appearance as off-site signs. A significant difference, however, is that the on-site sign is but a part of, and wholly incidental to, the business conducted upon the site and which the ordinance has properly determined to bе permissible in that district. Off-site signs, on the contrary, constitute a wholly
*380
distinct business, that of outdoor advertising (see opinion of Brennan, J., in
United Advertising Corp.
v.
Borough of Raritan,
From other jurisdictions, plaintiffs cite only a trial court opinion
(Central Outdoor Advertising Co.
v.
Village of Evan-dale
(Ohio Ct. Com. Pleas)
It follows that section 12, which prohibits future construction of off-site signs in “U” districts, is valid, and to the extent that the judgment is contrary to this conclusion it must be reversed.
There remains the question of the validity of section 34. This section provides that those off-site advertising structures which under the ordinance become nonconforming uses must be removed after five years. It applies to such signs in “U” districts as well as in those restricted districts in which permitted uses arе specified in greater detail.
Obviously, there is a real distinction between legislation which merely prohibits future uses and that which compels discontinuance of existing uses. From the inception of zoning, it has been recognized that ultimate elimination of a nonconforming use may be effected by restrictions upon extension of the nonconforming building, prohibition of its replacement if it be destroyed, and proscription of renewal of the use after discontinuance. In general, the older casеs drew the line, however, at outright prohibition of continuance of the use after the effective date of the zoning ordinance
(Jones
v.
City of Los Angeles,
But such legislation is valid only if the pеriod of amortization be reasonable
(City of Santa Barbara
v.
Modern Neon-Sign Co., supra,
One who attacks a zoning ordinance as unreasonable, however, bears the burden of establishing this claim
(Beverly Oil Co.
v.
City of Los Angeles,
We hold that section 34 is valid insofar as it requires *382 removal of signs in H, F, O, K, L, B, Y and T districts, as to all of which the ordinance specifies in detail the character of the district and the uses permitted therein.
Our conclusion differs as to the “U” districts. As we have pointed out, these districts are designed as holding areas, whose rural character is to be maintained only until some definite trend toward particular uses begins to develop. The ordinance recognizes that these areas have not reached a point of development warranting more specific regulation. While some may develop as districts in which off-sitе signs are barred, it is the very essence of this concept that some may develop as commercial or industrial zones, in which off-site signs are permitted. We have held that it is reasonable to prevent hindrance of such development by barring thе mushrooming of easily installed off-site signs and by limiting a number of offensive uses through requiring use permits therefor. It is quite another thing, however, to require removal of such signs in areas whose ultimate use is not now determinable. Upholding that portion of the removal requiremеnt could well result in destruction today of a sign which could be rebuilt in the near future.
When a particular “U” district has developed sufficiently to warrant placing it in a specific district, it will be time enough to resort to the remedy of removal.
Prohibition of new sign construction merely keeps the channels of growth and development free of diversion by billboards, until such growth has determined the uses to be permitted and those to be barred. To compel removal before that time is to yield to caprice, rаther than reason.
The judgment is affirmed insofar as it enjoins application of section 34 to “U” districts. In all other respects it is reversed, and the trial court is directed to enter judgment in accordance with the views herein expressed. Each party shall bear its own costs on appeal.
Salsman, J., and Devine, J., concurred.
A petition for a rehearing was denied January 23, 1963,
