Washington SWPPP inspection requirements
- Rain trigger
- Any discharge from the site (no rain-inch threshold)
- Post-rain deadline
- Within 24 hours
- Routine inspections
- Every 7 days
- Permit
- Construction Stormwater General Permit (2026)
- Agency
- Washington State Department of Ecology (Ecology)
How Washington handles construction stormwater
Construction sites in Washington disturbing one acre or more need coverage under the Construction Stormwater General Permit (2026), administered by Washington State Department of Ecology. The reissued CSWGP is effective January 1, 2026 – December 31, 2030. Inspect at least weekly and within 24 hours of any discharge from the site (multi-day discharge events don't require daily inspections). Weekly turbidity sampling now applies to all sites.
Inspector qualifications
Inspections by a Certified Erosion and Sediment Control Lead (CESCL) — required on all sites under the 2026 permit, regardless of size.
Official sources
Common questions
What triggers a SWPPP inspection in Washington?
Under the Construction Stormwater General Permit (2026), any discharge from the site (no rain-inch threshold) triggers an inspection, within 24 hours. Routine inspections: every 7 days.
Who can perform SWPPP inspections in Washington?
Inspections by a Certified Erosion and Sediment Control Lead (CESCL) — required on all sites under the 2026 permit, regardless of size.
Who administers the construction stormwater program in Washington?
Washington State Department of Ecology (Ecology) administers the NPDES construction stormwater program in Washington under the Construction Stormwater General Permit (2026).
What are the penalties for SWPPP violations in Washington?
Federal Clean Water Act civil penalties can reach $68,445 per day per violation, and Ecology can issue administrative orders and state penalties on top. Missing rain-triggered inspections is among the most commonly cited violations in stormwater audits.
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