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King County is required to provide surface water management services by state and federal law. The surface water management programs address impacts from stormwater runoff such as  flooding, erosion, pollution, habitat degradation, and low stream flows. To pay for these services, a fee is assessed on property owners in unincorporated King County including Vashon Island.

King County is committed to reducing the impact from stormwater runoff and protecting water quality to improve the health of Puget Sound. We do this for environmental as well as public health and safety reasons.

Services we provide

  • Design and construct capital projects to improve drainage and water quality, stabilize ravines, and restore fish and wildlife habitats.
  • Respond to and resolve more than 1,000 customer service calls per year regarding flooding, water quality problems, and erosion.
  • Offer drainage assistance to farmers and neighborhoods.
  • Work with commercial business owners, farmers, livestock owners, and forest land owners to implement "best management practices."
  • Inspect and maintain more than 2,000 flow control and water quality facilities such as retention/detention ponds, bio-swales, and off-road ditches.
  • Promote volunteer stewardship through planting events, habitat restoration, and property tax-incentive programs.
  • Monitor King County streams and lakes and recruit volunteer stewards to protect lake quality.
  • Develop basin plans and management plans for "non-active" resource lands.
  • Provide the science for King County's response to the Endangered Species Act, basin planning, land use decisions, and public education.

Brief history of King County's surface water management program and fee

Surface water management services have been in place for property owners in the unincorporated western third of King County since 1986. In 1999, the service area was expanded to cover the rest of unincorporated King County, including Vashon Island.

Over the years, the King County Council has raised the surface water management fee from time to time to ensure continued protection and improvement of  drainage and water quality. Effective January 1, 2013, the fee rate increased and will increase again in 2014 to:

  • Repair aging facilities;
  • Accelerate projects to reduce polluted runoff from roads and restore habitat;
  • Continue direct assistance to farmers and residential landowners;
  • Manage infrastructure effectively to reduce costly emergency maintenance; and
  • Comply with more rigorous state stormwater regulations.

For more information on why the SWM fee has increased in 2013 and 2014, please refer to our Surface Water Managment (SWM) fee fact sheet (197 Kb Acrobat pdf).

How current fees are calculated

King County's surface water management fee is based on the average amount of impervious surface on residential properties.

  • Residential property owners pay a flat $151 annual fee in 2013 and $171.50 in 2014.
  • The fee for non-residential property owners is based on how much of their parcel is impervious (for example, buildings, roads, and parking lots) and the size of the parcel.
  • Low-income senior citizens and the disabled are exempt.
  • Discounts and a cost-sharing program are available to encourage property owners to implement good stormwater management practices and reduce the amount of impervious surface on their parcels.

King County's fees are in the middle range of what other cities and counties in our region charge landowners. For more detailed information about the current surface water management fee and how you can qualify for a discount or apply for the cost-sharing program, please refer to:

For more background on the surface water management fee, you can read the 2012 Surface Water Management Rate Study.

How fees are collected and spent

King County Treasury Operations collects surface water management fees and they appear on your property tax statement. While not a tax, these fees are like other fees for service (from local fire or library districts for example). The Treasury Office distributes fee revenue to the Department of Natural Resources and Parks to pay for surface water management services, some of which are listed above.

In 2012, approximately $20.8 million was generated from surface water fees. This money is used to protect the quality of life for King County's citizens and to protect water and land resources from the impacts of development.

Contact information

Please call the reception desk at King County's Water and Land Resources Division 206-477-4800 to talk with a surface water customer service representative.

Visit the common questions and answers page for answers to other surface water management-related questions. For more detailed, technical information about SWM fee measurement, discount requirements, how to apply for a cost-sharing grant or about pervious surface credits, refer to SWM fee protocols document.