Flood Zones: Cambridge vs Somerville
How do flood zones rules compare between Cambridge, MA and Somerville, MA?
Cambridge and Somerville have similar restriction levels.
Cambridge, MA
Middlesex County
Cambridge participates in the National Flood Insurance Program and enforces a Flood Plain Overlay District covering FEMA Special Flood Hazard Areas along the Charles River and Alewife Brook.
View full Cambridge rules →Somerville, MA
Middlesex County
Parts of Somerville near the Mystic River and Alewife Brook are FEMA Zone AE. New construction in the floodplain must elevate 2 feet above BFE.
View full Somerville rules →Key Facts Comparison
| Fact | Cambridge | Somerville |
|---|---|---|
| Program | NFIP participant | - |
| Main flood areas | Charles, Alewife | - |
| Elevation | Above BFE plus freeboard | - |
| Insurance | Required for SFHA mortgages | Required in SFHA with mortgage |
| Future risk | Climate Vuln Assessment | - |
| Zones present | - | AE and X-shaded |
| Freeboard | - | 2 feet above BFE |
| Substantial improvement | - | 50 percent rule |
| Key areas | - | Mystic River, Alewife Brook, Assembly |
Highlighted rows indicate differences between cities.
Cambridge FAQ
Is my Cambridge property in a flood zone?
Check the FEMA Map Service Center and the Cambridge GIS portal using your address to see FEMA zone designation.
Do I need flood insurance?
Federally-backed mortgages in SFHAs require flood insurance; it is recommended even in moderate-risk areas.
Somerville FAQ
How do I find out if my Somerville property is in a flood zone?
Enter your address at the FEMA Map Service Center (msc.fema.gov) to pull the FIRM panel and Base Flood Elevation, or call Somerville Planning for a letter.
Can I finish my basement in a flood zone?
Enclosed space below BFE must be used only for parking, access, or storage and needs flood vents. Habitable finishes below BFE are prohibited for substantial improvements.
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