Stormwater Management: Redmond vs Seattle
How do stormwater management rules compare between Redmond, WA and Seattle, WA?
Redmond and Seattle have similar restriction levels.
Redmond, WA
King County
Redmond is an NPDES Phase II city and enforces Department of Ecology stormwater standards. Development over 2,000 sf of new or replaced impervious surface must mitigate runoff.
View full Redmond rules →Seattle, WA
King County
Seattle enforces comprehensive stormwater management under SMC Title 22 Subtitle VIII, requiring drainage control plans for all development and redevelopment to protect Puget Sound water quality.
View full Seattle rules →Key Facts Comparison
| Fact | Redmond | Seattle |
|---|---|---|
| Permit | NPDES Phase II | - |
| Manual | DOE 2019 Western WA | - |
| Trigger | 2,000 sf new impervious | - |
| Salmon basins | Bear Creek, Sammamish River | - |
| Governing Code | - | SMC Title 22, Subtitle VIII – Stormwater Code |
| Trigger Threshold | - | 750 sq ft of new or replaced impervious surface |
| Oversight Agency | - | Seattle Department of Construction and Inspections (SDCI) |
| Fee Structure | - | Drainage utility fee based on impervious surface area |
| Design Standard | - | Seattle Stormwater Manual with on-site BMP requirements |
Highlighted rows indicate differences between cities.
Redmond FAQ
Do I need a stormwater plan for a Redmond remodel?
Yes if the project creates or replaces more than 2,000 sf of impervious surface, with smaller projects requiring a basic form.
Can I wash my car at home in Redmond?
Private residential car washing is allowed; commercial washing that drains into a storm drain is an illicit discharge and is prohibited.
Seattle FAQ
Do homeowners pay stormwater fees in Seattle?
Yes, Seattle Public Utilities charges a drainage fee to all developed properties based on the amount of impervious surface. Residential properties pay a flat rate per parcel while commercial properties are charged based on measured impervious area. Credits are available for installing approved on-site stormwater management facilities like rain gardens.
When is a drainage control plan required?
A drainage control plan reviewed by SDCI is required for any project that adds or replaces 750 square feet or more of impervious surface, or that involves land-disturbing activity. This includes new construction, additions, and significant remodels.
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