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Sewer rate

The Wastewater Treatment Division sends its rate proposal to the King County Executive each spring. After review, the rate proposal goes to the King County Council for further deliberation. The council is required to adopt the sewer rate by June 30 for the following year. King County's overarching goal is to keep rates level for several consecutive years whenever possible. The county's regional wastewater utility runs on only revenues from the rates we charge our customer agencies. It does not use any tax money for wastewater collection, treatment and reclamation. View frequently asked questions.

Under long-term agreements with local sewer agencies in its service area, King County charges each agency a monthly amount for providing wastewater treatment. That amount is based on King County's monthly sewer rate and the number of customers served by the local agency. In turn, the local agencies bill the residences, businesses and industries in their wastewater collection system to recover the county charge plus the amount needed to operate their local collection systems.

The 2022 monthly sewer rate is $49.27 for single-family residences. The charge for multifamily, commercial, and industrial customers is $49.27 for each 750 cubic feet of water used.


Capacity charge

Since 1990, King County has levied a capacity charge on new connections to the sewer system, which these new customers pay in addition to their monthly sewer bill. The capacity charge helps King County cover the cost of sewer improvement and expansion projects needed to serve new growth.

Newly connecting customers are directly billed by King County for the capacity charge.

Elected officials, sewer utility representatives, and jurisdiction officials were all involved in King County's decision to implement a capacity charge to ensure that "growth pays for growth." Learn more about the capacity charge program.

County's wholesale monthly sewer rate $49.27
*Monthly capacity charge $70.39
*Listed rates are for 1 residential customer equivalent (RCE) per month. Capacity charge rates go into effect for new sewer hook-ups on or after January 1 each year.