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Stormwater facility discount
Residential and non-residential property owners may be eligible for surface water management (SWM) fee discounts for managing runoff using King County-approved flow control facilities, water quality facilities, features and/or best management practices (BMPs).
Qualifying residential parcels may receive a discount equal to 50 percent of the current residential fee. Call Stormwater Services Section customer service at 206-477-4811 for more information on how to qualify a parcel for a discount.
Qualifying facilities and practices can be found in the King County Surface Water Design Manual.
The non-residential discount program offers percentage discounts up to a maximum 90 percent discount for these stormwater controls:
- A maximum 20 percent discount for flow control facilities that meet any current or previous King County standard of design.
- A maximum 20 percent discount for flow control facilities that meet modern design standards adopted in the 1990 or later versions of the King County Surface Water Design Manual.
- A maximum 20 percent discount for flow control best management practices or infiltration facilities meeting King County standards that infiltrate or disperse runoff into pervious areas on the parcel to minimize the impact to the surface water system.
- A maximum 20 percent discount for King County standard water quality treatment facilities that meet King County design standards that remove pollutants from runoff before it flows to the surface water system or to groundwater.
- A 10 percent discount for parcels where stormwater discharges from at least 50 percent of the parcel are regulated under a National Pollutant Discharge Elimination System (NPDES) stormwater permit. Call Stormwater Services Section customer service at 260-477-4811 for more information on how to qualify a parcel for a discount.
Cost share and credit program
We have some limited funding available for stormwater retrofit grants. Stormwater retrofits are improvements made to existing developed parcels to reduce the impacts of stormwater runoff. These retrofits may also qualify a parcel for SWM fee discounts.
Non-residential properties trying to reduce impervious areas may be eligible for 50 percent of costs up to $20,000 by converting those areas to:
- native-vegetated landscape or
- compost-amended lawn or
- grassed, modular-grid pavement
Projects are chosen based on the total cost of the project and how much stormwater the project is expected to treat. Stormwater retrofits meeting the goals of this program often include those that also qualify for our RainScapes program.
See Section 4 of the SWM Fee Protocols (217 KB) for more information on this grant funding and how to apply for it.
Our engineers can answer your questions about what is needed to submit a proposal and the responsibilities of the property owner in fulfilling the cost-share project. Cost-sharing is available on a first come, first served basis until the annual funds are spent; the cost share is payable once the project has been completed and inspected.
Discount for forested or native conditions
Residential and non-residential property owners may qualify for a 65-10 discount if the parcel:
- is at least 65 percent forested or native condition; and
- has no more than 20 percent effective impervious area; and
- has no more than 10 percent effective impervious area (areas that flow directly to drainage systems without using flow control best managements practices to disperse or infiltrate runoff); and
- any impervious area over 10 percent uses flow control best management practices for dispersing or infiltrating runoff.
A residential parcel may qualify to receive a discount equal to half the residential fee. Non-residential parcels may qualify to receive a discount of 80 percent of the SWM fee. We will verify your parcel conditions. Other conditions may apply and at least one site visit by our engineers will be required for approval. This discount may not be combined with other runoff mitigation discounts.
Open space discount
Non-residential properties that are classified as open space per King County Code 9.08.010, may be eligible for an Public Benefit Rating System (also known as Open Space) discount.