Stormwater Management: Lowell vs Somerville
How do stormwater management rules compare between Lowell, MA and Somerville, MA?
Lowell and Somerville have similar restriction levels.
Lowell, MA
Middlesex County
Lowell enforces a local Stormwater Management Ordinance under its MS4 permit, requiring erosion controls and on-site management for projects over 1 acre or 5,000 square feet of disturbance.
View full Lowell 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 | Lowell | Somerville |
|---|---|---|
| Permit authority | EPA MS4 NPDES | - |
| Permit threshold | 5,000 sq ft disturbance | - |
| TSS removal | 80 percent | - |
| Illicit discharge | Prohibited | - |
| 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.
Lowell FAQ
Do I need a stormwater permit for a new driveway?
Only if the combined disturbance exceeds 5,000 square feet. Smaller projects still must avoid directing runoff onto neighbors or streets.
Can I wash my car in the driveway?
Occasional residential car washing is allowed, but commercial washing that discharges to the storm drain is considered an illicit discharge.
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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