TRAYNOR, J. The county of San Diego brought this action to compel the removal of four gasoline storage tanks allegedly erected- in violation of a county zoning ordinance. Judgment was- -entered for defendants, and the county appeals.
[685]Defendants’ property is about a mile from the center of Lemon Grove, a suburban area whose center is approximately 8 miles northeast of the business center of the city of San Diego. At the time of the filing of this action this area was predominantly residential with some local business and industry centered around the intersection of Broadway, the principal east-west arterial, and Imperial Boulevard, the principal north-south arterial. Business establishments were located east and west from this intersection along both sides of Broadway and were spottily distributed elsewhere throughout the area. Defendants’ land is on the southwest corner of the intersection of Broadway and Massachusetts Avenue, north-south arterial approximately one mile from Imperial Boulevard. The land is rectangular in shape and extends 660 feet south from Broadway and 1,760 feet west from Massachusetts Avenue.
The trial court found that continuously since 1938 defendants have used their property, with the exception of a small part not material to this action, for heavy industrial purposes, including above-ground storage of gasoline and other fuels, storage of paint for industrial painting, wholesale storage and sale of lumber, storage of steel beams and parts of machinery for heavy manufacturing, storage of rock, sand, and gravel, storage of junk and old iron, manufacture of acetylene gas and metal bearings, automobile and truck wrecking, building and rebuilding of heavy machinery, boiler repair shop, commercial planing mill, sandblasting, welding, heavy manufacturing processes using up to 2000 horsepower in the operation of machines, and general heavy construction contracting business. The court also found that defendants have used the entire premises as a unit in carrying out such uses, and that the part of defendants’ land where the tanks in question are situated has been used for the.foregoing industrial purposes. When defendants undertook this use of their land, the neighboring area was nearly all undeveloped, with virtually no residences.
In 1942 the county adopted Ordinance No'. 268 (New Series) as part of a comprehensive zoning plan for the Lemon Grove area. This ordinance divided defendants’ property into three districts. A retail business district, O-l, included the area extending south for 150 feet from the south property line on Broadway, thence from Massachusetts' to the west edge of defendants’ land; a wholesale business section, C-2, included approximately the west two thirds of defendants’ land, [686]running south from the C-l zone for an additional 330 feet; and a residential district, R.-2-A, extending south from the C-l zone, which included one third of defendants’ land.
In 1948 defendants erected a retail gasoline station near the intersection of Broadway and Massachusetts Avenue. The service station was within the area zoned for retail business, which permitted that use. Defendants also erected four tanks to provide storage facilities for the service station. Although the tanks are near the service station, they extend approximately 50 feet within the area zoned for residences. Before 1942 steel beams and trusses had been stored on this corner and there was a preliminary leveling of the land and a service road made thereon. There is no disagreement among any of the witnesses, however, that until the tanks in question were erected there were no permanent structures of any kind on this corner before or after 1942.
The trial court concluded that the tanks were permitted under a provision of the ordinance exempting nonconforming uses existing at the time of its adoption.
Section 17 of Ordinance 371, incorporated by reference in Ordinance 268 (New Series) provides:
“The lawful use of land existing at the time of the passage of this ordinance, although such use does not conform to the provisions hereof, may be continued; if such nonconforming use is discontinued any future use of said land shall be in conformity with the provisions of this ordinance. ’ ’
Such a provision is ordinarily included in zoning ordinances because of the hardship and doubtful constitutionality of compelling the immediate discontinuance of nonconforming uses. (See Jones v. City of Los Angeles, 211 Cal. 304 [295 P. 14].) “The object of such a provision is the gradual elimination of the nonconforming use by obsolescence or destruction by fire or the elements, and it has been frequently upheld by the courts.” (Rehfeld v. San Francisco, 218 Cal. 83, 84 [21 P.2d 419].) There is a growing tendency to guard against the indefinite continuance of nonconforming uses by providing for their liquidation within a prescribed period. (See 35 Va.L.Rev. 348, 356; Standard Oil Co. v. City of Tallahassee, 183 F.2d 410, 413, cert. den., 340 U.S. 892 [71 S.Ct. 208, 95 L.Ed. 647]; State ex rel. Dema Realty Co. v. McDonald, 168 La. 172 [121 So. 613], cert. den. 280 U.S. 556 [50 S.Ct. 16, 74 L.Ed. 612]; State ex rel. Dema Realty Co. v. Jacoby, 168 La. 752 [123 So. 314].)
[687]Given the objective of zoning to eliminate nonconforming uses, courts throughout the country generally follow a strict policy against their extension or enlargement.1
The evidence most favorable to defendants is that in their nonconforming use they utilized fuel tanks that were moved on heavy skid timbers from place to place as they were needed. One tank had a capacity of 1,200 gallons, another 2,300 gallons, and the largest a capacity of 6,000 gallons. Now, however, they have four new tanks with a capacity of 12,000 gallons each, that are 32 feet high and 8 feet in diameter and are permanently located upon a rectangular concrete base 10 feet wide and 54 feet long. In erecting four new tanks double the size of the largest of the old, defendants have not only increased their fuel storage capacity more than five times but have permanently affixed the tanks within the area zoned for residences. Such a formidable expansion can hardly be viewed as a mere continuance of the nonconforming use consisting of the intermittent storage of [688]lumber and scrap metal, preliminary grading, steel beam storage, or even the use of movable- tanks ‘1 all over the property, first one spot and then another” that may have occurred in the area in question. Even if the new tanks were used to supply power for the original industrial use, they would constitute an unwarranted enlargement of that nonconforming use. (See Rehfeld v. San Francisco; Yuba City v. Cherniavsky; Piccolo v. West Haven; De Felice v. East Haven; Thayer v. Board of Appeals; Ware v. Wichita; Colati v. Jirout; Inspector of Bldgs. of Burlington v. Murphy; Town of Marblehead v. Rosenthal; Town of Burlington v. Dunn; Austin v. Older; Women’s Christian Ass’n. of Kansas City v. Brown; In re Botz; Home Fuel Oil Co. v. Glen Rock; DeVito v. Pearsall; Pisicchio v. Board of Appeals; People v. Giorgi; State ex. rel. City Ice & Fuel Co. v. Stegner; Appeal of Yocom; supra note 1.)
The new tanks involve not merely an expansion of a nonconforming use but a new nonconforming use. The permitted use was for the storage of fuels to be consumed in supplying power as an incident to the industrial use; the new tanks are used as an incident to the service station use. The continuance of a nonconforming use “is a continuance of the same use and not some other kind of use.” (Kensington Realty Holding Corp. v. Jersey City, 118 N.J.L. 114 [191 A. 787, 788]; Simone v. Peters, 135 N.J.L. 495 [53 A.2d 315]; Home Fuel Oil Co. v. Glen Rock; Town of Lexington v. Bean; In re Botz; Women’s Christian Ass’n. of Kansas City v.. Brown; Appeal of Yocom; supra, note 1.) Defendants never conducted a service station on their premises until 1948, six years after the adoption of the ordinance. Although the service station is permitted in its location, the tanks are not permitted in the residence zone where defendants erected them. No one may erect such tanks in this residential district, and it would be an unwarranted discrimination in favor of defendants to hold that they may do so. (Rehfeld v. San Francisco, supra, 218 Cal. 83, 85; Pisicchio v. Board of Appeals, 165 Misc. 156 [300 N.Y.S. 368, 369-370].)
Even if it be assumed that the tanks did not involve a new nonconforming use of the land, their construction was prohibited by the second paragraph of section 17 of Ordinance 371, which provides:
“The lawful use of a building existing at the time of the passage of this ordinance may be continued, although such [689]use does not conform with the provisions hereof; such use may be extended throughout the building provided no structural alterations, except those required by law or ordinance, are made therein. If no structural alterations are made, a non-conforming use of a building may be changed to another non-conforming use of the same or more restricted classifications.”
A “building” is defined in section 1 of ordinance 371 as “a structure having a roof supported by columns or walls.” “Structure” is defined as “anything constructed or erected and use of which requires more or less permanent location on the ground or attachment to something having a permanent location on the ground.” It has been held that “building” includes a water tank (State v. Ornelas, 42 N.M. 17 [74 P.2d 723, 725]); a dugout or- artificial cave (State v. Clark, 221 Mo.App. 893 [288 S.W. 77]); a silo (Bush v. Norman (Mo.App.) 199 S.W. 721); a 35-foot steel tower and 60-barrel steel storage tank supported thereby (Griffin v. Holland, 191 Okla. 417 [131 P.2d 113]); an iron fence (Swasey v. County of Shasta, 141 Cal. 392, 394 [74 P. 1031]); a sand-hopper (Wilbur v. City of Newton, 302 Mass. 38 [18 N.E.2d 365, 368]; a billboard (Goodrich v. Selligman, supra, note 1; for numerous other illustrations see 12 C.J.S. 382.) Thus, there can be no doubt that the four new tanks are “buildings” within the meaning of the ordinance. Although the prohibition of structural alterations does not preclude ordinary routine repair and maintenance of existing buildings (see 58 Am.Jur. Zoning, § 156, p. 1026) it does preclude the erection of new buildings. If an old building cannot be enlarged, a fortiori a new building caiinot be built. (Rehfeld v. San Francisco; Yuba City v. Cherniavsky; Piccolo v. West Haven; Goodrich v. Selligman; Colati v. Jirout; Connors v. Town of Burlington; Inspector of Bldgs. of Burlington v. Murphy; Cole v. Battle Creek; Women’s Christian Ass’n. of Kansas City v. Brown; DeVito v. Pearsall; Benjamin v. Lietz; supra, note 1; see 8 McQuillin, Municipal Corporations, 3d ed. 1950, § 25. 205, p. 393.)
Defendants contend that they would have constructed all necessary facilities at the beginning to complete the full industrial development of their property had they had capital enough and that since they “had to finish the plant as they could earn it, one building at a time,”- they gained.a vested right to continue the development of their land until its full [690]industrial use had been reached. The purpose of the landowner in purchasing the property must yield to the public interest in the enforcement of a comprehensive zoning plan. (Wilkins v. City of San Bernardino, 29 Cal.2d 332, 337 [171 P.2d 542]; Acker v. Baldwin, 18 Cal.2d 341, 344 [115 P.2d 455]; Sunny Slope Water Co. v. City of Pasadena, 1 Cal.2d 87, 93-94 [33 P.2d 672]; cf. Skalko v. City of Sunnyvale, 14 Cal.2d 213, 215 [93 P.2d 93].) The intention to expand the business in the future does not give defendants the right to expand a nonconforming use. (Town of Billerica v. Quinn, 320 Mass. 687 [71 N.E.2d 235, 236]; Chayt v. Board of Zoning Appeals of Baltimore City, 17 Md. 426 [9 A.2d 747, 750]; Appeal of Kiddy, supra, note 1.) The ordinance has made allowance for the continuance of nonconforming uses existent in 1942; it does not permit the enlargement of such uses as the owners find expansion desirable. It is immaterial that a property owner in an area zoned for residential purposes contemplated the maximum commercial utilization of his property previous to the zoning ordinance. (Sunny Slope Water Co. v. City of Pasadena, 1 Cal.2d 87, 95 [33 P.2d 672]; O’Rourke v. Teeters, 63 Cal.App.2d 349, 352 [146 P.2d 983]; Marblehead Land Co. v. City of Los Angeles, 36 F.2d 242, 244; 47 F.2d 528, 534, cert. den. 284 U.S. 634 [52 S.Ct. 18, 76 L.Ed. 540]; Ware v. City of Wichita, 113 Kan. 153 [214 P. 99]; Spector v. Building Inspector of Milton, 250 Mass. 63 [145 N.E. 265]; Chayt v. Board of Zoning Appeals of Baltimore City, supra.) Although defendants are confined in their nonconforming use to the activities carried on at the time their property was zoned, they enjoy a favored position compared to those who purchased property for a nonconforming use and were prevented from using it at all for that purpose because their property was zoned before they could establish such a use.
Defendants rely on In re Smith, 143 Cal. 368 [77 P. 180] and Dobbins v. Los Argeles, 195 U.S. 223, 224 [25 S.Ct. 18, 49 L.Ed. 169]. In the Smith case the gas works had been erected before the passage of the ordinance. It exemplifies the rule that a lawful use existing at the time a zoning ordinance becomes effective cannot be prohibited when it is not a public nuisance. In the Dobbins case the owner undertook construction of a gas works in a permitted area and expended some $2,500 in erecting the foundation before a zoning ordinance was passed prohibiting gas works in that district. [691]If an owner has legally undertaken the construction of a building before the effective date of a zoning ordinance, he may complete the building and use it for the purpose designed after the effective date of the ordinance. (City of Coldwater v. Williams Oil Co., 288 Mich. 140 [284 N.W. 675]; Best & Co. v. Incorporated Village of Garden City, 286 N.Y.S. 980, aff’d. 273 NY. 564 [7 N.E.2d 694].) Protection of an undertaking involving the investment of capital, the purchase of equipment, and the employment of workers, is akin to protection of a nonconforming use existing at the time that zoning restrictions become effective. The same principle underlies the rule that a permittee who has expended substantial sums under a permit cannot be deprived by a subsequent zoning ordinance of the right to complete construction and to use the premises as authorized by the permit. (Trans-Oceanic Oil Corp. v. Santa Barbara, 85 Cal.App.2d 776 [194 P.2d 148]; Sandenburgh v. Michigamme Oil Co., 249 Mich. 372 [228 N.W. 707]; Atlantic Broadcasting Co. v. Wayne Tp., 109 N.J.L. 442 [162 A. 631]; Nassau-Fulton Realty Corp. v. Schlimm, 67 N.Y.S.2d 501; People v. Bales, 224 App.Div. 87 [229 N.Y.S. 550].)
Defendants contend that they are being discriminated against on the ground that neighboring owners were granted variances and that over half the lands within a radius of the intersection of Broadway and Massachusetts Avenue were being used for heavy industrial purposes. There was a sharp conflict in the evidence as to the extent and nature of the other nonconforming uses in this area. The trial court made no finding on this issue, and the evidence does not establish unjust discrimination as a matter of law. No zonng ordinance can classify districts with perfect justice. Since cases of unusual hardship may require variances, zoning authorities are usually given power to grant them. The fact that variances may have been granted to some owners and denied to others, however, does not establish unreasonable discrimination. The granting or denial of variances rests largely in the discretion of the body designated by the zoning ordinance for that purpose, and a denial of a variance will not be disturbed in the absence of a clear showing of abuse of discretion. (Rubin v. Board of Directors, 16 Cal.2d 119 [104 P.2d 1041]; Otis v. City of Los Angeles, 52 Cal.App.2d 605, 613 [326 P.2d 954]; Larkin Co., Inc. v. Schwab, 242 N.Y. 330, 336 [151 N.E. 637, 639]. As to the degree of discretion vested in such bodies, see Lockard v. Los Angeles, 33 Cal.2d [692453], 461 [202 P.2d 38, 7 A.L.R.2d 990]; Acker v. Baldwin, 18 Cal.2d 341, 344 [115 P.2d 455].)
Judgment reversed.
Gibson, C. J., Edmonds, J., and Spence, J., concurred.
Rehfeld v. San Francisco, 218 Cal. 83, 85 [21 P.2d 419]; Burke v. City of Los Angeles, 68 Cal.App.2d 189, 191 [156 P.2d 28]; Yuba City v. Cherniavsky, 117 Cal.App. 568, 573 [4 P.2d 299]; Wilson v. Edgar, 64 Cal.App. 654, 657 [222 P. 623]; De Felice v. East Haven, 130 Conn. 156 [32 A.2d 635, 147 A.L.R. 161]; Piccolo v. West Haven, 120 Conn. 449 [181 A. 615, 617]; Thayer v. Board of Appeals, 114 Conn. 15 [157 A. 273, 276]; Ware v. Wichita, 118 Kan. 265 [234 P. 978]; Goodrich v. Selligman, 298 Ky. 863 [183 S.W.2d 625, 627]; Dorman v. Baltimore, 187 Md. 678 [51 A.2d 658, 661]; Colati v. Jirout, 186 Md. 652 [47 A.2d 613, 615-616]; Beyer v. Mayor and City of Baltimore, 182 Md. 444 [34 A.2d 765, 769]; Connors v. Town of Burlington (1950), Mass. [91 N.E.2d 212, 213]; Inspector of Bldgs. of Burlington v. Murphy, 320 Mass. 207 [68 N.E.2d 918, 919]; Town of Burlington v. Dunn, 318 Mass. 216 [61 N.E.2d 243, 247, 168 A.L.R. 1181]; Town of Marblehead v. Rosenthal, 316 Mass. 124 [55 N.E.2d 13]; Town of Lexington v. Bean, 272 Mass. 547 [172 N.E. 867, 870]; Cole v. City of Battle Creek, 298 Mich. 98 [298 N.W. 466, 468]; Austin v. Older, 283 Mich. 667 [278 N.W. 727, 729]; Women’s Christian Ass’n. of Kansas City v. Brown, 354 Mo. 700 [190 S.W.2d 900, 906]; In re Botz, 236 Mo.App. 566 [159 S.W.2d 367, 371-373]; Lynch v. Borough of Hillsdale, 136 N.J.L. 129 [54 A.2d 723, 725-726]; Albright v. Johnson, 135 N.J.L. 70 [50 A.2d 399]; Burmore Co. v. Smith, 124 N.J.L. 541 [12 A.2d 353, 356]; Home Fuel Oil Co. v. Glen Rock, 118 N.J.L. 340 [192 A. 516, 518]; De Vito v. Pearsall, 115 N.J.L. 323 [180 A. 202]; Conaway v. Atlantic City, 107 N.J.L. 404 [154 A. 6]; Village of Ossining v. Meredith, 73 N.Y.S.2d 897; People v. Giorgi, 16 N.Y.S.2d 923; Pisicchio v. Board of Appeals, 165 Misc. 156 [300 N.Y.S. 368, 369]; State ex rel. City Ice & Fuel Co. v. Stegner, 120 Ohio St. 418 [166 N.E. 226, 227, 64 A.L.R. 916]; Appeal of Kiddy, 294 Pa. 209 [143 A. 909]; Appeal of Yocom, 142 Pa. Super. 165 [15 A.2d 687, 689-690]; Meserolo v. Board of Adjustment, City of Dallas, (Tex. Civ. App.) 172 S.W.2d 528, 530-531; Benjamin v. Lietz, -Utah- [211 P.2d 449, 451]; see 147 A.L.R. 167; 8 McQuillin, Municipal Corporations, 3d ed. 1950, § 25.183, pp. 366-367.