Idaho SWPPP inspection requirements

The short version
Rain trigger
0.25″ storm event
Post-rain deadline
Within 24 hours
Routine inspections
Every 7 or 14 days
Permit
IPDES Construction General Permit
Agency
Idaho Department of Environmental Quality (IDEQ)

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

How Idaho handles construction stormwater

Construction sites in Idaho disturbing one acre or more need coverage under the IPDES Construction General Permit, administered by Idaho Department of Environmental Quality. Idaho took over NPDES permitting from EPA in 2021 (IPDES program); its CGP closely mirrors the federal permit.

Inspector qualifications

A qualified person designated by the operator. Check the current state permit for certification requirements.

Official sources

Common questions

What triggers a SWPPP inspection in Idaho?

Under the IPDES Construction General Permit, a storm event of 0.25 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 Idaho?

A qualified person designated by the operator. Check the current state permit for certification requirements.

Who administers the construction stormwater program in Idaho?

Idaho Department of Environmental Quality (IDEQ) administers the NPDES construction stormwater program in Idaho under the IPDES Construction General Permit.

What are the penalties for SWPPP violations in Idaho?

Federal Clean Water Act civil penalties can reach $68,445 per day per violation, and IDEQ 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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