Stormwater permits in Renton: fees, timeline & requirements (2026)
Everything you need to know about pulling a stormwater / drainage permit in Renton, Washington — when one is required, what it costs, how long review takes, what documents are required, and which inspections you can expect. Cited to Renton Community and Economic Development — Development Services.
Free lookup, no account needed — your lot polygon, zoning, setbacks and overlays, cited to Renton's source.
When does drainage work need a permit in Renton?
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 Renton's own code
“EXEMPTIONS: No person shall do any mining, excavation or grading without first having obtained a special permit from the Hearing Examiner and an annual license issued by the Development Services Division with the concurrence of the Building Official, except for the following: 1. An excavation below finished grade for basements and footings of a building, retaining wall or other structure authorized by a valid building permit.”Source ↗verified 2026-05-17
What Renton says in its own permit handout
From Building Permits FAQ, published by Renton. This is the jurisdiction's own guidance on its permit process, not the ordinance text — where the two differ, the code governs.
“Civil Construction and/or Utility Permits: a permit may be required when a project is proposed to result in: More than 500 square feet of new or replaced impervious area. More than 7,000 square feet of land disturbing activity.”Handout ↗read 2026-09-05
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 Renton?
Kolmo Construction is a licensed Washington general contractor — KOLMOL*753JS, active through April 10, 2027, bonded and insured — working throughout Renton and King County. Kolmo prepares the drawings and submittals, files the stormwater / drainage permit with Renton Community and Economic Development — Development Services, carries the project through review and inspections, and performs the construction. Call (206) 410-5100 for a Renton 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 Renton — 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: Renton Community and Economic Development — Development Services ↗
- 4. Track review. Respond to reviewer comments promptly.
- 5. Pay issuance fees (Renton'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 Renton Community and Economic Development — Development Services, handles reviewer comments, and builds the project.
Licensed WA general contractor KOLMOL*753JS · bonded & insured
Stormwater permits in Renton — FAQ
When does drainage work need a permit in Renton?
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 Renton?
Renton's storm water system development charge is $2,350 for a new house or ADU, and $0.94 a square foot, up to $2,350, for an addition over 500 square feet. A surface water connection permit is $375. Clearing, grading and new or replaced hard surface of 500 sq ft or more is priced by tier: Tier 1 (50 to 499 cubic yards, or 500 to 4,999 sq ft of hard surface) is $553 review and $532 inspection. The City adds its 5% technology surcharge to each of these fees (Fee Schedule 2025-2026). Apply via https://permitting.rentonwa.gov.