Wash. Rev. Code § 90.03.345
The establishment of reservations of water for agriculture, hydroelectric energy, municipal, industrial, and other beneficial uses under RCW 90.54.050(1) or minimum flows or levels under RCW 90.22.010 or 90.54.040 shall constitute appropriations within the meaning of this chapter with priority dates as of the effective dates of their establishment. Whenever an application for a permit to make beneficial use of public waters embodied in a reservation, established after September 1, 1979, is filed with the department of ecology after the effective date of such reservation, the priority date for a permit issued pursuant to an approval by the department of ecology of the application shall be the effective date of the reservation.
RCW 90.03.345
Effective date-Severability-1979 ex.s. c 216: See notes following RCW 90.03.245.