Questions and Answers

The Stormwater Facility Credit Program provides a discount on drainage bills for private stormwater systems that reduce stormwater flow and/or provide water quality treatment, which help lessen the impact to the City of Seattle's stormwater systems. Systems must be built to City Code standards and be properly maintained and functioning to be considered for credit.


Frequently Asked Questions

What is a stormwater system?

Stormwater systems are structures such as vaults, rain gardens, permeable pavements and infiltration systems that provide water quality treatment and/or slow down stormwater flow from impervious surfaces like rooftops, driveways or walkways. Retrofitted systems can also apply as long as they meet code requirements.

How do I know if I have a stormwater system on my property?

Here are four ways you can determine if you have a stormwater system on your property. Some of these systems may have access points that are in landscaped areas or parking lots where you may need to expose the access point.

  • Locate plans used for original development and/or redevelopment of your property. Review the drainage plans for pipes and stormwater systems such as detention vaults or oil water separators.
  • Evaluate your property while it is raining. Starting from the roof downspouts and catch basins, follow the path of the water to see and hear where it goes. You might need a crowbar to open grates and a flashlight to inspect the downstream pipes for the direction of flow. Follow flow to see if there are any structures in that direction.
  • Look at your property’s sewer side sewer card. These site maps will outline the drainage structures on your property and may show any vaults or treatment systems that were constructed during the construction phase. Look up your address at Seattle's Department of Planning and Development Side Sewer Cards & Maps.

If my application is approved, when can I expect to see the credit on my drainage bill?

All applications received by November 1 are eligible for credit on the drainage bill for the next calendar year. The drainage bill is shown on the annual property tax bill from the King County Assessor.

How big will my credit be?

Credit amounts are both site and system specific. The maximum allowable parcel credit is 50 percent. In 2008, the average awarded credit was 9 percent.

Do I have to reapply for the credit program every year?

No, the credit will continue to remain on your account as long as your stormwater system is operating and maintained properly. Seattle Public Utilities' drainage fee is billed on the King County property tax statement. Learn more about SPU's drainage rates.

You can view your current drainage fee by entering your property tax account number into the King County Property Tax Information System. The drainage fee is shown as the "Surface Water" or "Drainage" line item on the statement and will be net of any approved credits. Your property tax account number is found on the property tax statement you receive in the mail from King County. You may also find your property tax account number (or parcel number) by using the "Parcel Viewer" search feature found at the above King County Web site.

What are the benefits of building a low impact development system?

Low-impact development (LID) and Green Stormwater Infrastructures (GSI) systems, such as rain gardens and swales, generally provide a higher level of stormwater management and thus receive a larger credit than traditional stormwater systems such as detention vaults. Low impact development is a way to decrease the amount of impervious surface on your property during the development and/or construction phases. By decreasing the amount of impervious surface, you reduce the amount of rainwater runoff from the site onto the City street and right-of-ways.

How often will my system be inspected?

SPU may inspect systems once a year.

What if the inspector tells me I need to clean my system?

If your stormwater system has not been properly maintained or is not working properly, you will have one month to repair, clean and maintain the system before a second inspection. Failure of a second inspection will terminate your credit. Non-functioning systems may be subject to follow-up enforcement actions as required by code.

I own a condo. How do I get a credit for stormwater systems that manage my building's run-off?

If your condo property has a stormwater system, each unit in the condo may be eligible for stormwater facility credit. Any approved facility credit will be shared equally among owners of individual units. To be considered for a credit, your condo homeowner association will need to submit an application form. If the application is approved, you will receive the credit on the surface water fee that is billed on your individual unit's property tax statement. The condo association will be responsible for ensuring that the necessary maintenance is completed in order to continue receiving the credit.

I own a townhouse with no homeowners' association. How do I get this stormwater facility credit?

If your townhouse development has no homeowners' association, any individual owner may submit an application. Any approved credit will be divided among the townhouses in the development. SPU requires all stormwater systems be properly maintained in order to qualify for and continue to receive a facility credit. In the absence of a homeowners' association, townhouse owners must work out the details regarding system maintenance among themselves. Often, guidelines regarding maintenance of common systems are addressed in covenants specific to the townhouse development.


Public Utilities

Andrew Lee, General Manager and CEO
Address: 700 5th Avenue, Suite 4900, Seattle, WA, 98104
Mailing Address: PO Box 34018, Seattle, WA, 98124-5177
Phone: (206) 684-3000

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Seattle Public Utilities (SPU) is comprised of three major direct-service providing utilities: the Water Utility, the Drainage and Wastewater Utility, and the Solid Waste Utility.