Stormwater permits in Sammamish: fees, timeline & requirements (2026)
Everything you need to know about pulling a stormwater / drainage permit in Sammamish, Washington — when one is required, what it costs, how long review takes, what documents are required, and which inspections you can expect. Cited to Sammamish Community Development.
Free lookup, no account needed — your lot polygon, zoning, setbacks and overlays, cited to Sammamish's source.
When does drainage work need a permit in Sammamish?
Ecology's Stormwater Management Manual for Western Washington (SWMMWW, 2024 edition) is the state floor. A municipal stormwater permittee may instead adopt a regional manual Ecology has determined equivalent, and most do — some counties publish their own, some cities publish their own, and others adopt Ecology's directly. Which manual applies is a per-jurisdiction fact and it changes the numbers: review thresholds for new plus replaced impervious surface and for land-disturbing activity differ between manuals, so read this jurisdiction's own adopting chapter before quoting one. Critical-area and closed-basin parcels get stricter review under every manual.
From Sammamish's own code
“All clearing and grading activities must be associated with an approved land use and exceptions do not apply to properties that are undeveloped and do not have an approved land use. No clearing and grading activities may occur on undeveloped properties without a permit associated with an approved land use. On sites without an approved land use the removal of hazardous trees, invasive species, and noxious weeds is allowed with issuance of a clearing and grading permit.”Source ↗verified 2026-05-29
Required submittals
- Drainage report (full or simplified)
- Site plan with impervious calc
- BMP / facility detail
- Geotech if infiltration claimed
Inspection sequence
- Pre-construction (BMPs in place)
- Facility installation
- Final stabilization
Contractor specialties needed
General contractor
Who can do this work in Sammamish?
Kolmo Construction is a licensed Washington general contractor — KOLMOL*753JS, active through April 10, 2027, bonded and insured — working throughout Sammamish and King County. Kolmo prepares the drawings and submittals, files the stormwater / drainage permit with Sammamish Community Development, carries the project through review and inspections, and performs the construction. Call (206) 410-5100 for a Sammamish stormwater / drainage quote.
Notes & caveats
Issuing body is city public works / county DPER, often parallel to the building permit. On-site infiltration / detention required where infeasible to discharge to municipal storm. Critical-area parcels (steep slope, salmon-bearing watercourse) get more conservative review.
How to apply yourself
- 1. Confirm your parcel's zoning & overlays. Run an address lookup for your drainage work in Sammamish — we'll pull your specific lot polygon, zoning, setbacks, and any shoreline, critical-area or historic overlays.
- 2. Assemble submittals: the 4 documents under Required submittals above.
- 3. Submit through the city portal: Sammamish Community Development ↗
- 4. Track review. Respond to reviewer comments promptly.
- 5. Pay issuance fees (Sammamish's fee schedule sets them) and pick up the permit. Inspection card travels with the job.
Or have Kolmo do it
Kolmo prepares the drawings and submittals, files with Sammamish Community Development, handles reviewer comments, and builds the project.
Licensed WA general contractor KOLMOL*753JS · bonded & insured
Stormwater permits in Sammamish — FAQ
When does drainage work need a permit in Sammamish?
Ecology's Stormwater Management Manual for Western Washington (SWMMWW, 2024 edition) is the state floor. A municipal stormwater permittee may instead adopt a REGIONAL manual Ecology has determined equivalent, and most do — some counties publish their own, some cities publish their own, and others adopt Ecology's directly. WHICH MANUAL APPLIES IS A PER-JURISDICTION FACT and it changes the numbers: review thresholds for new plus replaced impervious surface and for land-disturbing activity differ between manuals, so read this jurisdiction's own adopting chapter before quoting one. Critical-area and closed-basin parcels get stricter review under every manual.
How much does a stormwater / drainage permit cost in Sammamish?
Sammamish reviews clearing and grading twice: a minor clear and grade permit, up to 100 cubic yards, is a $267 Planning base fee and a $543 Public Works base fee. A drainage adjustment review takes a $4,000 deposit against its actual cost. The City's stormwater utility rate is $504.68 a year for a residence. The City adds a 15% technology fee to each fee (2026 Fee Schedule). Apply via https://mybuildingpermit.com.