Key Facts Full Breakdown Violations FAQ Sources

Post Falls, ID Environmental Rules: Stormwater Management (2026)

Heavy Restrictions

Researched & edited by Martyn O'NeillHow we verify

Verified April 2026

Key Facts

Trigger area: 1+ acres disturbed
Permit: IPDES CGP IDR100000
Authority: Idaho DEQ
Statute: Idaho Code 39-3601
SWPPP required: Yes, on-site

Idaho state rule: Post Falls does not have a local ordinance for stormwater management. This topic is governed by Idaho state law and applies uniformly across the state.

Summary

The Idaho Pollutant Discharge Elimination System (IPDES) program, administered by the Department of Environmental Quality under Idaho Code Title 39 Chapter 36, requires construction sites disturbing one or more acres to obtain stormwater coverage. State permits preempt conflicting local discharge standards.

Full Breakdown

EPA delegated NPDES authority to Idaho in 2018, and the Department of Environmental Quality (DEQ) now administers the IPDES program under Idaho Code 39-3601 et seq. Construction operators that disturb one or more acres, or are part of a common plan disturbing one acre, must obtain coverage under the IPDES Construction General Permit (CGP IDR100000). The CGP requires a Stormwater Pollution Prevention Plan (SWPPP), best management practices for sediment and erosion control, regular inspections by qualified personnel, and post-construction stabilization. Industrial facilities and certain Municipal Separate Storm Sewer System (MS4) operators require separate IPDES permits. Cities may adopt stricter local stormwater ordinances under their MS4 permits but cannot relax IPDES discharge limits.

Violations & Fines

Discharging without a required IPDES permit can result in DEQ enforcement orders, civil penalties up to $10,000 per day, and federal Clean Water Act liability for repeat violations.

Frequently Asked Questions

When do I need a stormwater permit for construction?

When the project disturbs one acre or more, or is part of a larger common plan of development disturbing one acre. You must obtain coverage under the IPDES Construction General Permit before starting earthwork.

Can my city require a SWPPP for smaller sites?

Yes. Cities operating under MS4 permits often require erosion control plans for sites under one acre. Local rules can be stricter than IPDES but cannot waive state requirements.

What happens if I discharge without a permit?

DEQ may issue compliance orders and civil penalties. The federal Clean Water Act authorizes additional fines up to $25,000 per day for unpermitted discharges to waters of the United States.

Sources & Official References

Stormwater Management in Other Cities

Los Angeles, CA New York, NY Chicago, IL Houston, TX Phoenix, AZ San Francisco, CA

How does Post Falls compare?

See how Post Falls's stormwater management rules stack up against other locations.

Compare to Another Location View Idaho Overview

See something wrong?

Help us keep this page accurate. If you notice an error or outdated information, let us know.

Key Facts Full Breakdown Violations FAQ Sources

Post Falls, ID Environmental Rules: Stormwater Management (2026)

Heavy Restrictions

Researched & edited by Martyn O'NeillHow we verify

Source: →

Verified April 2026

Key Facts

Trigger area: 1+ acres disturbed
Permit: IPDES CGP IDR100000
Authority: Idaho DEQ
Statute: Idaho Code 39-3601
SWPPP required: Yes, on-site

Idaho state rule: Post Falls does not have a local ordinance for stormwater management. This topic is governed by Idaho state law and applies uniformly across the state.

Summary

Full Breakdown

Violations & Fines

Discharging without a required IPDES permit can result in DEQ enforcement orders, civil penalties up to $10,000 per day, and federal Clean Water Act liability for repeat violations.

Frequently Asked Questions

When do I need a stormwater permit for construction?

Can my city require a SWPPP for smaller sites?

Yes. Cities operating under MS4 permits often require erosion control plans for sites under one acre. Local rules can be stricter than IPDES but cannot waive state requirements.

What happens if I discharge without a permit?

DEQ may issue compliance orders and civil penalties. The federal Clean Water Act authorizes additional fines up to $25,000 per day for unpermitted discharges to waters of the United States.

Sources & Official References

Stormwater Management in Other Cities

Los Angeles, CA New York, NY Chicago, IL Houston, TX Phoenix, AZ San Francisco, CA

How does Post Falls compare?

See how Post Falls's stormwater management rules stack up against other locations.

Compare to Another Location View Idaho Overview

See something wrong?

Help us keep this page accurate. If you notice an error or outdated information, let us know.

Post Falls, ID Environmental Rules: Stormwater Management (2026)

Key Facts

Summary

Full Breakdown

Violations & Fines

Frequently Asked Questions

Popular Rules in Post Falls, ID, ID

Sources & Official References

Related Post Falls Ordinances

Landscaping Rules: Composting

Landscaping Rules: Artificial Turf

Landscaping Rules: Native Plants

Landscaping Rules: Rainwater Harvesting

Landscaping Rules: Water Restrictions

Landscaping Rules: Weed Ordinances

Stormwater Management in Other Cities

How does Post Falls compare?

Get notified when Stormwater Management in Post Falls, ID changes

See something wrong?

Post Falls, ID Environmental Rules: Stormwater Management (2026)

Key Facts

Summary

Full Breakdown

Violations & Fines

Frequently Asked Questions

Popular Rules in Post Falls, ID, ID

Sources & Official References

Related Post Falls Ordinances

Landscaping Rules: Composting

Landscaping Rules: Artificial Turf

Landscaping Rules: Native Plants

Landscaping Rules: Rainwater Harvesting

Landscaping Rules: Water Restrictions

Landscaping Rules: Weed Ordinances

Stormwater Management in Other Cities

How does Post Falls compare?

Get notified when Stormwater Management in Post Falls, ID changes

See something wrong?