CWA §402: EPA Construction Stormwater General Permit

Regulatory citation: Clean Water Act §402 (33 U.S.C. 1342); 40 CFR 122.26; EPA 2022 NPDES General Permit for Discharges from Construction Activities (2022 CGP), as modified

What Is the Construction General Permit?

Under the Clean Water Act's NPDES program, stormwater from a construction site needs permit coverage if the project disturbs one acre or more, or is part of a larger common plan of development or sale that will.

EPA issues the Construction General Permit (CGP) only where it is the NPDES permitting authority. That includes Massachusetts, New Hampshire, New Mexico, the District of Columbia, the territories and most Indian country. Other states issue their own, broadly similar permits.

Why Construction Stormwater Matters

Bare soil erodes fast. One storm can wash sediment and other pollutants into streams and storm drains. Discharging without coverage, or ignoring permit terms, is a Clean Water Act violation.

Core Obligations

1. Prepare a SWPPP Before Applying (Part 1.4.1 and Part 7)

Each operator must develop a Stormwater Pollution Prevention Plan (SWPPP) before filing for coverage. It describes the site, the stormwater team, controls and inspection procedures, and must be kept current.

2. File a Notice of Intent (Part 1.4)

Operators submit a Notice of Intent (NOI) electronically at least 14 calendar days before earth disturbance begins. Coverage starts 14 calendar days after EPA confirms receipt of a complete NOI, unless EPA delays or denies it. Post a notice of coverage near the site where the public can see it.

3. Install Erosion and Sediment Controls (Part 2.2)

Controls must be in place before work starts in each area. Key measures include perimeter controls, a 50-foot natural buffer (or equivalent controls) next to receiving waters, track-out controls, inlet protection and contained stockpiles.

4. Meet Stabilization Deadlines (Part 2.2.14)

Stabilization must begin immediately, meaning by the end of the next business day, once work stops in an area for 14 or more days. Sites with five acres or less disturbed at one time must finish stabilizing within 14 calendar days. Larger disturbances, and sites discharging to sensitive or impaired waters, have 7 calendar days. Final vegetative stabilization means uniform perennial cover of at least 70 percent of the native background cover.

5. Inspect the Site (Part 4)

A qualified person must inspect at least every 7 calendar days, or every 14 calendar days and within 24 hours of a storm producing 0.25 inches of rain or more. Sites discharging to sensitive or impaired waters must do both. Reduced frequencies apply to stabilized, arid or frozen areas. Inspection reports are due within 24 hours and must be kept for three years after coverage ends. Inspectors need EPA inspector training or an equivalent certification.

6. Take Corrective Action (Part 5)

When a control fails or a permit condition is not met, start fixing it immediately. Simple fixes must be done by the close of the next business day. New or replacement controls and significant repairs must be working within 7 calendar days, or you must document why that is not feasible. Record each corrective action.

7. Terminate Coverage (Part 8)

File a Notice of Termination (NOT) within 30 calendar days after you finish earth disturbance and reach final stabilization, transfer control to another permitted operator, or obtain coverage under another permit. Include before and after photos.

Common Compliance Approaches

Use EPA's SWPPP Template

EPA publishes a SWPPP template and inspection forms that match the CGP, which helps cover every required element.

Tie Inspections to a Rain Gauge

An on-site rain gauge shows when a 0.25-inch storm triggers an inspection and provides proof for auditors.

Example: Construction Stormwater in Practice

A contractor plans a three-acre retail project in New Mexico, where EPA issues the permit. The team writes a SWPPP, files the NOI three weeks before groundbreaking and posts the coverage notice at the entrance. Silt fence and a stabilized exit go in before grading. After a half-inch storm, the inspector finds a silt fence breach, reports it that day and has it repaired the next morning. Once paving and grass cover are complete, the contractor files the NOT with photos.

Related regulations: EPA industrial stormwater (NPDES), EPA SPCC oil spill prevention, OSHA excavation and trenching standard.

Note: The 2022 CGP expires at 11:59 pm on February 16, 2027. EPA proposed a replacement 2027 CGP in August 2026, which had not been finalized at the time of writing. Check EPA's CGP page for the current permit before filing.

Frequently Asked Questions

Do I need a permit if my lot is under one acre?

Possibly. A small lot needs coverage if it is part of a larger common plan, such as a subdivision, that will disturb one acre or more.

Which permit applies in my state?

In most states the state agency issues it. EPA's CGP applies only in the areas listed in Appendix B of the permit.

Who counts as an operator?

Anyone with control over the plans and specifications, or day-to-day control of activities affecting compliance. Often both the owner and general contractor need coverage.