Last Updated 08/19/2026
Androscoggin Stormwater Laws & Regulations
Androscoggin Valley has been authorized by the State of Maine to operate a Municipal Separate Storm Sewer System (MS4) permit within 4 municipalities. These 4 municipalities have created similar stormwater management plans to reduce discharge of pollutants into stormwater. Unless otherwise noted, the permit regulation only covers the identified Urban Areas within Androscoggin Valley.
The Androscoggin Valley Stormwater Management Program encompasses 4 Urban Areas:
- City of Lewiston
- City of Auburn
- Town of Sabattus
- Town of Lisbon
EXCERPT- Androscoggin Valley SWMP
5. MCM #5 POST-CONSTRUCTION STORMWATER MANAGEMENT
Each permittee shall develop, implement, and enforce a program to address stormwater runoff from new development and redevelopment projects that disturb greater than or equal to one acre, including projects less than one acre that are part of a larger common plan of development or sale, that discharge into the MS4. This program shall ensure that controls are in place that will prevent or minimize water quality impacts.
5.2 ANNUAL INSPECTION OF POST CONSTRUCTION BMPS
(Maine DEP MS4 Permit Part IV.H.5.a.iii)
Each permittee shall annually inspect a percentage of post construction BMPs located in the direct watershed of a lake most at risk from new development or in watersheds of an urban impaired stream. If the owner or operator of a post construction BMP hires a qualified third party inspector, the permittee will have no inspection requirements. If the owner or operator of a post construction BMP does a “self” inspection, the permittee is required to conduct the following inspection schedule.
- 1-10 post construction sites: inspect at least one site, or 40% (whichever is greater)
- 11-30 post construction sites: inspect at least four sites, or 30% (whichever is greater)
- 31-60 post construction sites: inspect at least nine sites, or 25% (whichever is greater)
- 61-100 post construction sites: inspect at least fifteen sites, or 20% (whichever is greater)
- 101-160 post construction sites: inspect at least twenty sites, or 17% (whichever is greater)
- Over 160 post construction sites: inspect at least twenty seven sites, or 11% (whichever is greater)
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Frequently Asked Questions
What is the Androscoggin Valley Stormwater Management Program?
It’s an MS4 permit authorized by the State of Maine, covering four Urban Areas: the city of Lewiston, the city of Auburn, the town of Sabattus, and the town of Lisbon. Each municipality has developed its own stormwater management plan to reduce pollutant discharge, and unless otherwise noted, the permit only applies within these identified urban areas.
What triggers post-construction stormwater management requirements in Androscoggin Valley?
Any new development or redevelopment project disturbing 1 acre or more that discharges into the MS4 requires a stormwater runoff management program. This also includes smaller projects under 1 acre that are part of a larger common plan of development or sale. Each permittee municipality must develop, implement, and enforce controls that prevent or minimize water quality impacts from these projects.
Who inspects post-construction BMPs in Androscoggin Valley, and how often?
If a property owner hires a qualified third-party inspector for their post-construction BMP, the permittee municipality has no separate inspection obligation for that site. If the owner does a self-inspection instead, the municipality must inspect a set percentage of sites annually, focusing on watersheds most at risk from new development or urban impaired streams.
What percentage of post-construction BMPs get inspected each year in Androscoggin Valley?
The rate depends on how many post-construction sites the municipality oversees. For 1 to 10 sites, at least one site or 40% gets inspected, whichever is greater. That share scales down as site counts grow: 30% for 11 to 30 sites, 25% for 31 to 60, 20% for 61 to 100, 17% for 101 to 160, and 11% for anything over 160, always with a minimum number of sites guaranteed regardless of percentage.
How does the Androscoggin Valley program relate to individual town ordinances like Sabattus and Lisbon?
The AVSWG program sets the shared regional framework and annual inspection requirements for post-construction BMPs across all four member municipalities. Individual towns like Sabattus and Lisbon layer their own post-construction stormwater management codes on top of this framework, including their own certification deadlines and maintenance agreement requirements for property owners within town limits.
The information on this page is provided for general informational purposes only and is not legal advice. Regulations change frequently — AQUALIS makes no warranty as to the accuracy or completeness of this content, and any reliance on it is at your own risk. Consult a qualified professional or your local regulatory authority to confirm requirements applicable to your specific property.
