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Sewage Treatment Capacity Charge

Growth paying for growth

King County
Wastewater Treatment Division
Capacity Charge Program
201 S. Jackson,
M.S. KSC-NR-0502
Seattle, WA 98104

Phone: 206-296-1450
Fax: 206-263-6073
E-mail: CapChargeEscrow

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.”

  • Effective January 1, 2014, the county's monthly capacity charge for new connections increased to $55.35; the wholesale monthly sewer rate remains at $39.79. View June 10, 2013 news release.
  • King County offers the option to pay off the capacity charge at a discount when all outstanding invoices are paid in full. Effective January 1, 2014, the discount rate has been revised to more closely reflect economic trends.
  • Frequently asked questions about the sewage treatment capacity charge.
  • Paying your invoice online - when paying online, you will need your invoice (view sample invoice) to locate and enter the Account Number and Site Number. Payments can be made through your checking account (e-check) or by credit card (Visa and Master Cards are accepted). This payment option is being offered at no additional charge to customers.

2014 Sewage Treatment Capacity Charge
Frequently asked questions about sewage treatment capacity charge (PDF), effective January 1, 2014
To request print versions, please contact us at or 206-296-1450.
En Espanol: Cargo por Capacidad de Tratamiento de Aguas Residuales (PDF)