RCW 57.02.100Single-family homes and townhouses—Multipurpose fire sprinkler systems.(1) A water-sewer district may not prohibit the use of multipurpose fire sprinkler systems that are part of a structure's plumbing system for single-family homes and townhouses as defined by the state residential building code or require a separate water meter or backflow preventer for the multipurpose fire sprinkler system.(2) For the purposes of this section, 'multipurpose fire sprinkler system' means a fire sprinkler system that:(a) Is supplied only by the purveyor's water;(b) Does not have a fire department pumper connection;(c) Is constructed of approved potable water piping and materials to which sprinkler heads are attached; and(d) Terminates at a connection to a toilet or other plumbing fixture to prevent stagnant water.[ 2016 sp.s. c 14 s 1.]
Washington Legal Code