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Stormwater Directory

Maine

Maine Department of Environmental Protection

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Quick Summary

For most Maine projects disturbing 1 acre or more, you need a state Construction General Permit and a SWPPP. Inspectors must hold an active CESCL, CESSWI, or CPESC — one of the few states mandating a specific named certification.

State-DelegatedVerified 2026-03

Construction Permit

Permit Document ↗
Permit Name
Maine Multi-Sector General Permit for Stormwater Discharges — Construction Activity (Permit No. MER10I000)
Threshold
≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale)
NOI Lead Time
NOI must be submitted and acknowledged before land disturbance begins; no fixed statutory lead time specified in permit, but DEP recommends submitting at least 14 days before construction
Application Method
Paper NOI submitted to Maine DEP; online submission available through the Maine DEP e-permitting portal (EDEP) for some applications
Fee
$200 NOI filing fee for sites disturbing 1–4.99 acres; $500 for sites disturbing ≥ 5 acres; fees payable to Treasurer, State of Maine
Permit Expires
February 16, 2028
Apply for Permit ↗

SWPPP Requirements

Permit Document ↗
SWPPP Required
Yes
PE Cert Required
No
Template Available
Yes
SWPPP must be prepared prior to submitting the NOI and must be kept on-site and available for inspection. Maine DEP provides a SWPPP template and guidance document. The SWPPP preparer must be knowledgeable in the principles of erosion and sediment control but a PE stamp is not required by the general permit. Certified Erosion and Sediment Control Lead (CESCL) training is strongly encouraged.

Inspection Requirements

Permit Document ↗
Frequency
Every 7 days and within 24 hours after any storm event producing ≥ 0.5 inches of rainfall in a 24-hour period; inspection frequency may be reduced to every 14 days for stabilized areas
Rain Trigger
Within 24 hours of a storm event producing ≥ 0.5 inches of rainfall in a 24-hour period
Inspector Qualification
Inspections must be conducted by a person knowledgeable in the principles and practice of erosion and sediment control; Maine DEP strongly recommends Certified Erosion and Sediment Control Lead (CESCL) — a nationally recognized credential — but it is not mandated by the permit
Accepted Certifications
State-approved CESCL (Certified Erosion and Sediment Control Lead), CESSWI, or CPESC REQUIRED for site inspectors; Maine DEP enforces this requirement

Discharge Standards

Permit Document ↗
Turbidity Limit
No numeric NTU limit specified in the construction general permit; narrative standard requires discharges not to cause or contribute to violations of Maine's water quality standards (Class A, B, or C waters)
Maine water quality standards prohibit discharges that cause turbidity, color, or other conditions that unreasonably affect existing or designated uses. Sites discharging to Outstanding River Segments or Class AA/GPA waters face additional protective requirements. Visual monitoring of discharge points is required at each inspection.

Post-Construction

DEP ↗
Required
Yes
Maine Stormwater Management Law (38 M.R.S. §420-D) requires post-construction stormwater management for projects disturbing ≥ 1 acre in a Tier 2 or higher water or in a shoreland zone. Separate DEP Stormwater Management permits (Tier 1, 2, or 3) govern post-construction runoff and must be obtained in addition to the construction general permit for applicable sites.

Impaired Waterbody / TMDL Requirements

Elevated Risk

Maine DEP construction stormwater permit includes heightened protection for Class AA and Class A waters (highest quality designated uses). Projects that may impact Class AA waters require the most stringent controls; individual permit review may be required. Maine's strong antidegradation policy under the Maine Water Classification Program (38 M.R.S. § 464-470) protects high-quality waters from degradation.

Program Contact

Contact Page ↗
Phone
(207) 287-7688
Email
DEP.PBRNotification@maine.gov

State-Specific Notes

Maine is a delegated NPDES state. Notably, Maine has a parallel state Stormwater Management permit program under 38 M.R.S. §420-D that applies post-construction and may require a separate Tier 1, 2, or 3 permit depending on project size and receiving water classification — this is distinct from and in addition to the construction general permit NOI. Sites near lakes, rivers, or coastal waters classified as Tier 3 (Outstanding Natural Resources Waters) face the most stringent requirements. Maine's shoreland zoning laws may also impose additional setback and disturbance restrictions.

Disclaimer: This information is provided for general reference only and may not reflect the most current regulatory requirements. Always consult the DEP website and applicable regulations before beginning any construction activity.