Idaho SWPPP inspection requirements
- Rain trigger
- 0.25″ storm event
- Post-rain deadline
- Within 24 hours
- Routine inspections
- Every 7 or 14 days
- Permit
- IPDES Construction General Permit (IDR100000)
- Agency
- Idaho Department of Environmental Quality (IDEQ)
How Idaho handles construction stormwater
Construction sites in Idaho disturbing one acre or more need coverage under the IPDES Construction General Permit (IDR100000), administered by Idaho Department of Environmental Quality. Idaho took over NPDES permitting from EPA in 2021; IDR100000 (effective February 10, 2022) closely mirrors the federal CGP — every 7 days, or every 14 days plus within 24 hours of a 0.25″ storm (3.25″ of snow causing discharge also triggers). The permit expires February 9, 2027 — watch for the reissuance.
Inspector qualifications
A qualified person who has completed EPA's construction inspection course and exam or holds an equivalent current certification (e.g., Idaho Construction Stormwater Inspector), or works under the supervision of someone who does.
Official sources
Common questions
What triggers a SWPPP inspection in Idaho?
Under the IPDES Construction General Permit (IDR100000), a storm event of 0.25 inches or more triggers a post-storm inspection, within 24 hours (non-work days typically extend to the next work day; check your permit). Routine inspections: every 7 or 14 days.
Who can perform SWPPP inspections in Idaho?
A qualified person who has completed EPA's construction inspection course and exam or holds an equivalent current certification (e.g., Idaho Construction Stormwater Inspector), or works under the supervision of someone who does.
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 (IDR100000).
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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