Washington State

Office of the Attorney General

Attorney General

Bob Ferguson

AGO 1954 No. 278 -
Attorney General Don Eastvold


A county ordinance imposing a classified density control in a residence district (R-1) of the county is constitutional.

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                                                                   June 24, 1954

Honorable Charles O. Carroll
Prosecuting Attorney of King County
County-City Building
Seattle 4, Washington                                                                                                 Cite as:  AGO 53-55 No. 278

Attention:  !ttMr. Paul C. Gibbs,Deputy Prosecuting Attorney

Dear Sir:

            In a recently acknowledged letter you ask the opinion of this office upon the validity of a contemplated calibrated density control provision in the county zoning code.  Specifically your question was whether the Board of County Commissioners may impose conditions of different minimum lot sizes in different parts of a residential zone (R-1).

            It is our opinion that such restrictions would be valid, where reasonable and based upon some substantial difference in fact, when necessary to promote the public health, safety, morals and general welfare.


            The general authority to regulate the density of population by zoning restrictions is given to the several counties by RCW 35.63.080:

             [[Orig. Op. Page 2]]

            "The council or board may provide for the preparation by its commission and the adoption and enforcement of coordinated plans for the physical development of the municipality.  For this purpose the council or board, in such measure as is deemed reasonably necessary or requisite in the interest of health, safety, morals and the general welfare, upon recommendation by its commission, by ordinance or resolution may regulate and restrict * * * the density of population; * * *"

            The purposes and reasons for such regulations are well stated by the next section of the Code, RCW 35.63.090:

            "All regulations shall be worked out as parts of a comprehensive plan which each commission shall prepare for the physical and other generally advantageous development of the municipality and shall be designed, among other things, to encourage the most appropriate use of land throughout the municipality; to lessen traffic congestion and accidents; to secure safety from fire; to provide adequate light and air; to prevent overcrowding of land; to avoid undue concentration of population; to promote a coordinated development of the unbuilt areas; to encourage the formation of neighborhood or community units; to secure an appropriate allotment of land area in new developments for all the requirements of community life; to conserve and restore natural beauty and other natural resources; to facilitate the adequate provision of transportation, water, sewerage and other public uses and requirements."

            There can be no doubt but that by these sections the legislature intended to authorize population density zoning.

            Such population control, of itself, has generally been recognized as a valid exercise of the police power, 141 A.L.R. 693; Rathkoff, the Law of Zoning and Planning, 464; Zoning Law and Practices, Yokley.  That type of control which  [[Orig. Op. Page 3]] establishes one minimum standard to apply alike throughout the entire controlled district has generally been upheld by the courts.  Simon v. Town of Needham, 42 N.E. (2d) 516; Gignoux v. Village of Kingsport, 99 N.Y.S. (2d) 280;Clemens v. City of Los Angeles, 222 P. (2d) 439; Euclid v. Ambler Realty Co., 272 U.S. 365, 71 L. Ed. 303, 47 S.Ct. 114.  Here, however, the problem is slightly different ‑ the minimum standards may vary in different parts of the controlled sections, especially outside the limits of a city.

            It would seem that because an area is classified for one purpose ‑ i.e., for residences ‑ this fact of itself would not prevent another classification, made upon a different basis, from being imposed upon the same area or some part of it.  Equal protection of the laws requires only that laws operate equally within a class; it does not require that once a class is established upon one basis, that it remain ever the same, in a real extent at least, preventing any future classifications of the same area, on a different basis.  If, in an existing R-1 residence zone, there is a substantial difference between all or any of its parts, then varying minimum lot size regulations may be superimposed upon the several parts so long as such classification has a reasonable basis in fact and the restrictions are a proper exercise of the police power.

            No proposed ordinance was submitted to this office, so we are not able to consider any specific applications.  Although this type of ordinance is not of itself illegal, it often runs afoul of the law in its application, and so should be treated with caution.  It often degenerates into a device for economic segregation.  While this may be an incident to a zoning program, it should be remembered that it cannot be the sole purpose.  As was said inSimon v. Town of Needham, 42 N.E. (2d) 516:

            "A zoning by-law [[bylaw]]cannot be adopted for the purpose of setting up a barrier against the influx of thrifty and respectable citizens who desire to live there and who are able and willing to erect homes upon lots upon which fair and reasonable restrictions have been imposed nor for the purpose of protecting the large estates that are already located in the district.  The strictly local interest of the town must yield if it appears that they are plainly in conflict with the general interests of the public at large, and in such  [[Orig. Op. Page 4]] instances the interest of 'the municipality would not be allowed to stand in the way.'"

Very truly yours,

Attorney General

Assistant Attorney General