Grading & Drainage: Cambridge vs Somerville
How do grading & drainage rules compare between Cambridge, MA and Somerville, MA?
Somerville has fewer restrictions than Cambridge.
Cambridge, MA
Middlesex County
Cambridge requires grading and drainage plans with building permits to ensure runoff is managed on-site and does not adversely affect neighbors or the municipal storm drain system.
View full Cambridge rules →Somerville, MA
Middlesex County
Grading over 50 cubic yards or that changes drainage patterns requires DPW review in Somerville. Roof and yard drainage may not discharge to neighbors.
View full Somerville rules →Key Facts Comparison
| Fact | Cambridge | Somerville |
|---|---|---|
| Permit review | ISD and DPW | - |
| Runoff | Managed on-site | - |
| Neighbor harm | Prohibited | - |
| Sump pump to sewer | Prohibited | - |
| Downspouts | To infiltration preferred | - |
| Permit trigger | - | 50 cubic yards or drainage change |
| Roof leaders | - | To storm or infiltration |
| Neighbor discharge | - | Prohibited |
| Retaining wall permit | - | Over 4 feet |
| Sump to sewer | - | Federal CWA violation |
Highlighted rows indicate differences between cities.
Cambridge FAQ
Can I regrade so water flows to my neighbor?
No, creating adverse drainage onto neighboring property violates city rules and exposes you to civil liability.
Where should my sump pump discharge?
To a lawn, drywell, or approved storm system; never to the sanitary sewer in Cambridge.
Somerville FAQ
Can I regrade my yard to drain away from my foundation?
Yes, as long as the new flow stays on your property or goes to the street or storm drain. You cannot redirect water onto a neighbor's lot without permission.
Do I need a permit to build a small retaining wall?
Walls up to 4 feet typically need only zoning clearance. Walls over 4 feet (measured from bottom of footing) need a building permit and engineered plans.
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