Washington SWPPP inspection requirements

The short version
Rain trigger
0.5″ storm event
Post-rain deadline
Within 24 hours
Routine inspections
Every 7 or 14 days
Permit
Construction Stormwater General Permit (CSWGP)
Agency
Washington State Department of Ecology (Ecology)

Verify against your permit. These values reflect the most common reading of Washington's program; permits change and projects vary. The official permit text from Ecology controls.

How Washington handles construction stormwater

Construction sites in Washington disturbing one acre or more need coverage under the Construction Stormwater General Permit (CSWGP), administered by Washington State Department of Ecology. Weekly inspections by a CESCL plus within 24 hours of any discharge or qualifying storm; sampling requirements (turbidity) apply to many sites.

Inspector qualifications

Inspections by a Certified Erosion and Sediment Control Lead (CESCL) — required on most permitted sites.

Official sources

Common questions

What triggers a SWPPP inspection in Washington?

Under the Construction Stormwater General Permit (CSWGP), a storm event of 0.5 inches or more triggers a post-storm inspection, generally due within 24 hours (non-work days typically extend to the next work day; check your permit). Routine inspections run every 7 or 14 days.

Who can perform SWPPP inspections in Washington?

Inspections by a Certified Erosion and Sediment Control Lead (CESCL) — required on most permitted sites.

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 (CSWGP).

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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