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(2) For seasonally used, transitory non-community, or <br />recreational developments the design for ADD, MDD, and <br />PHD shall be based upon metered water uses whenever such <br />data is available. The data must account for the daily <br />population using the water over the time that records are <br />collected, and must reflect the uses associated with maximum <br />occupancy for the development. The design demands for <br />these developments apply only to part-time uses, and may not <br />be applied to structures or dwellings that can be permanently <br />occupied. <br />I (3) In the absence of metered use or other comparable <br />information, the following sources of design information may <br />be used: <br />(a) Comparable metered water use data from analogous <br />water systems. Analogous systems are those with similar <br />characteristics, such as demographics, housing sizes, income <br />levels, lot sizes, climate, water pricing structure, water use <br />efficiency practices, use restrictions, and soils and <br />landscaping; or <br />(b) Design criteria or guidelines in the most recent edition <br />of the department manual for design of Group A public water <br />systems. <br />( 4) The design for water systems based upon metered <br />water use records shall have an MDD no lower than three <br />hundred fifty gallons per day per equivalent residential unit <br />(ERU), except for the design of any expansion to an existing <br />water system that has a minimum of two years of meter <br />records that clearly demonstrate that a lower design value for <br />MDD may be used without significant risk of pressure loss. <br />The meter records must correlate the demand data to the <br />actual level of occupancy for the periods covered by the <br />records. <br />(5) The minimum water demand and duration required for <br />fire flow and/or fire suppression storage shall be determined <br />by the local fire control authority or chapter 246-293 WAC <br />for systems within the boundaries of a designated critical <br />water supply service area (CWSSA). Public water systems <br />that are not required to comply with minimum fire flow <br />standards shall coordinate with the local fire control <br />authorities to ensure that any hydrants on the system, if they <br />25