Wash. Rev. Code § 19.260.080
(1) An electric storage water heater, if manufactured on or after January 1, 2021, may not be installed, sold, or offered for sale, lease, or rent in the state unless it complies with the following design requirement:
(a) The product must have a modular demand response communications port compliant with:
[ 2019 c 286 s 5.]