Skip to main content

About the surface water management fee

We are committed to protecting water quality, public health and safety, and restoring Puget Sound. We are also required by state and federal law to provide services that protect clean water, our rivers, lakes, and streams.

These services help with problems such as flooding, erosion, pollution, habitat degradation, low stream flows, and increased water temperatures. Changes to natural systems from development alters the way water moves over and through the land, and the pollutants it picks up along the way.

To pay for services that help resolve these problems, property owners in unincorporated King County pay a surface water management (SWM) fee.

What is surface water management?

Surface water management (SWM) combines landowner assistance, maintenance and construction projects, stewardship, regulatory requirements, and restoration programs to protect public health and safety, and the waters and lands in unincorporated King County. We use these tools to identify, fix, prevent, and lessen the impact of stormwater runoff and other water quality problems such as erosion, pollution, habitat degradation, and changes in water flow and temperature.

Surface Water Management Fee Protocols and Public Rule

On December 16, 2012, the King County Council passed Ordinance No. 17451 about surface water management (SWM). This ordinance revised SWM service charges and rate adjustments for nonresidential land parcels. As a result, changes were made to the SWM fee discount program for nonresidential parcels.

These changes created a tiered system of SWM fee discounts. This system recognizes the benefits of various levels and types of stormwater facilities and best management practices (BMPs) maintained by the property owner. The standards, rules, and procedures for how these discounts are applied to individual parcels are in the 2013 SWM Fee Protocols (631 KB). The 2013 SWM Fee Protocols were most recently revised in 2020.

Read the 2016 Policy Paper: Surface Water Management (270 KB)

Read the 2013 (Revised 2020) SWM Fee Protocols (632KB)

Read the Public Rule - Surface Water Management (SWM) Fee Protocols (287 KB)

When did this program fee start?

King County's SWM program and fee began in 1987 and is applied to parcel owners in unincorporated King County. Almost every city in King County has its own SWM program and assesses a fee to pay for it. Surface water management is a requirement of the federal Clean Water Act. Under that act, many counties and cities in the state and many businesses have a National Pollutant Discharge Elimination permit and are required to comply and protect water quality. As a result, many governments have SWM programs to address these requirements and charge a SWM fee to fund their programs.

Is this fee a tax?

By state statute and county code, the SWM fee is not a tax. The courts both in King and Clark counties have upheld this determination. Generally speaking, taxes are based on levels of income or some kind of valuation. Fees are charged based on a contribution to a problem and are earmarked funds that can be spent only on specific activities. The SWM fee is directly linked to the problems associated with runoff from impervious surfaces, and it pays for specific services and programs to identify, fix, or prevent those problems.

Do new housing and commercial developments pay this fee?

Yes, landowners for every developed parcel – residential or non-residential properties that have impervious surfaces – in unincorporated King County pay this fee unless they are exempt by King County Code or state law.

How does King County use the funds from the Surface Water Management fee?

By law, Surface Water Management fee funds must be, and can only be, spent on surface water management-related projects and services. Both state statutes and King County Code limit how these fees can be spent. Washington State and/or the King County auditors routinely audit the program to make sure that fee revenues are being spent according to the law and good accounting practices are being maintained. The annual county budget process also requires the Water and Land Resources Division to report to the King County Council and the Executive about how fee dollars are spent.

The Surface Water Management fees support these efforts:

  • Improving the condition of outdated stormwater flow structures under county roads that carry runoff
  • Managing stormwater assets, maintaining and replacing aging infrastructure. It’s important to keep infrastructure functioning through inspections, maintenance, repair, and replacement of aging structures. This helps avoid the potential high costs and disturbances of emergency repairs
  • Mapping the stormwater conveyance system in the county right-of-way
  • Increasing habitat restoration projects to improve water quality and help recover salmon populations
  • Supporting productivity of local farmers through the Agricultural Drainage Assistance Program and the Farm, Fish, and Flood effort
  • Addressing chronic drainage, flooding, and beaver management issues
  • Developing a new water quality grant program, called RainScapes, to assist residents and communities in making water quality improvements
  • Creating a discount program for low-income property owners to pay for SWM fees


Who benefits from the SWM fee?

Farmers and the agricultural community

Part of the fee pays for programs that help farmers and the agricultural community through:

Salmon and other native fish

Fee revenue is used to build projects that improve drainage, water quality, and stream bank stability that also improve fish habitat. A small amount pays for King County's part in salmon recovery efforts. To respond to the Endangered Species Act, there are four watershed areas in King County where groups of scientists, elected officials, and representatives from cities and community groups work together to protect salmon habitats. Improvements to fish habitat generally improve water quality too.


Where can I get more information?

For questions about your fee, call the Water and Land Resources customer services at 206-477-4800. To speak to a stormwater engineer about your parcel, call Stormwater Services Section customer service at 206-477-4811

We can put you in contact with your basin steward to learn what is happening in your area or you can visit the basin steward web page.