Stormwater Management: Ayer vs Somerville
How do stormwater management rules compare between Ayer, MA and Somerville, MA?
Ayer and Somerville have similar restriction levels.
Ayer, MA
Middlesex County
Stormwater follows the MA Wetlands Protection Act (MGL c.131 s.40), MassDEP Stormwater Standards, and municipal MS4 bylaws under the EPA NPDES permit.
View full Ayer rules →Somerville, MA
Middlesex County
Somerville is an EPA MS4 community. Projects disturbing 1 acre need NPDES permits; local review kicks in at 500 sq ft of new impervious surface.
View full Somerville rules →Key Facts Comparison
| Fact | Ayer | Somerville |
|---|---|---|
| State act | MGL c.131 s.40 | - |
| Wetlands regs | 310 CMR 10.00 | - |
| MS4 permit | EPA NPDES | - |
| Buffer | 100 ft of wetlands | - |
| Trigger acre | CGP at 1 acre | - |
| Federal permit | - | NPDES at 1 acre disturbance |
| Local trigger | - | 500 sq ft impervious |
| Design standard | - | No net peak runoff increase |
| Illicit discharge fine | - | Up to $5,000 per day |
| Watershed | - | Mystic River basin |
Highlighted rows indicate differences between cities.
Ayer FAQ
Who issues the local wetlands permit?
The municipal Conservation Commission, via a Notice of Intent filing.
Do small projects need stormwater BMPs?
Residential work may be exempt, but additions and new construction usually need at least infiltration measures.
Somerville FAQ
I am replacing my driveway with the same area. Do I need stormwater review?
Replacement in kind with no expansion generally does not trigger full review, but switching to a less-pervious surface or expanding the area over 500 square feet does.
Where does Somerville's stormwater go?
Most of the City drains to the Mystic River via MWRA and DCR systems, and some combined sewer areas flow to the Deer Island treatment plant during dry weather.
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