Wash. Rev. Code § 80.28.100
No gas company, electrical company, wastewater company, or water company may, directly or indirectly, or by any special rate, rebate, drawback or other device or method, charge, demand, collect or receive from any person or corporation a greater or less compensation for gas, electricity, wastewater company services, or water, or for any service rendered or to be rendered, or in connection therewith, except as authorized in this chapter, than it charges, demands, collects or receives from any other person or corporation for doing a like or contemporaneous service with respect thereto under the same or substantially similar circumstances or conditions.
RCW 80.28.100
Findings-Purpose-Limitation of chapter-Effective date- 2011 c 214 : See notes following RCW 80.04.010.
Reduced utility rates for low-income senior citizens and other low-income citizens: RCW 74.38.070.