The legislative body of any code city acting through a planning agency created pursuant to chapter 35A.63 RCW, or pursuant to its granted powers, may prepare a proposed zoning regulation to become effective upon the annexation of any area which might reasonably be expected to be annexed by the code city at any future time. Such proposed zoning regulation, to the extent deemed reasonably necessary by the legislative body to be in the interest of health, safety, morals and the general welfare may provide, among other things, for:

(1) The regulation and restriction within the area to be annexed of the location and the use of buildings, structures and land for residence, trade, industrial and other purposes; the height, number of stories, size, construction and design of buildings and other structures; the size of yards, courts and other open spaces on the lot or tract; the density of population; the setback of buildings and structures along highways, parks or public water frontages; and the subdivision and development of land;

(2) The division of the area to be annexed into districts or zones of any size or shape, and within such districts or zones regulate and restrict the erection, construction, reconstruction, alteration, repair or use of buildings, structures or land;

(3) The appointment of a board of adjustment, to make, in appropriate cases and subject to appropriate conditions and safeguards established by ordinance, special exceptions in harmony with the general purposes and intent of the proposed zoning regulation; and

(4) The time interval following an annexation during which the ordinance or resolution adopting any such proposed regulation, or any part thereof, must remain in effect before it may be amended, supplemented or modified by subsequent ordinance or resolution adopted by the annexing city or town.

All such regulations and restrictions shall be designed, among other things, to encourage the most appropriate use of land throughout the area to be annexed; 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.