(1) Water system plans prepared by those public water systems identified in WAC 248-57-200 shall include a section in their plans addressing fire flow, hydrant and system reliability standards in accordance with WAC 248-57-500, 248-57-600, and 248-57-700 respectively. The section shall include a map entitled development classifications consistent with the following:

(a) The map shall delineate the existing and future service area of the water system into the following categories:

(i) Rural - Lot sizes greater than one acre (including parks, open space, agricultural lands, etc.)

(ii) Residential - Lot sizes one acre or less, (including all single and multifamily structures less than 4000 square feet, and mobile home and recreational vehicle parks)

(iii) Commercial and multifamily residential structures with a floor area 4000 square feet or greater.

(iv) Industrial

(b) Assignment of the above categories shall be based upon:

(i) Existing development, and

(ii) Future development for a minimum of ten years as identified in proposed or adopted land use plans and policies applicable within the existing and future service area.

(c) The development classifications outlined in (a) above shall be determined by any method acceptable to the planning jurisdiction(s), provided that the criteria used is consistent within a given critical water supply service area.

(2) The water system plan shall identify and schedule improvements needed in order for the water system to be capable of supplying required fire flow for new and expanding public water systems consistent with these regulations.