Flood Zones: Boston vs Chelsea
How do flood zones rules compare between Boston, MA and Chelsea, MA?
Boston and Chelsea have similar restriction levels.
Boston, MA
Suffolk County
Boston enforces FEMA flood zone regulations through Zoning Code Article 25A and the city's Flood Hazard Overlay District. Properties in designated AE and VE zones must meet base flood elevation requirements. Boston's updated flood maps reflect sea level rise projections, and the city requires freeboard above BFE for new construction.
View full Boston rules →Chelsea, MA
Suffolk County
Chelsea has significant flood risk: 15% of the city is currently in SFHA (Zone AE near Chelsea Creek and Island End River); projected to reach 34% by 2081. FEMA revised Flood Insurance Rate Maps effective March 16, 2016. NFIP participation required; flood insurance mandatory for federally backed mortgages in SFHA.
View full Chelsea rules →Key Facts Comparison
| Fact | Boston | Chelsea |
|---|---|---|
| Zoning Article | Article 25A — Flood Hazard Overlay | - |
| Flood Area | ~10% of Boston in SFHA | - |
| Residential Freeboard | 1 foot above BFE | - |
| Critical Facility Freeboard | 2 feet above BFE | - |
| Sea Level Rise Projection | 40 inches by 2070 | - |
| SFHA Coverage | - | 15% of city (Zone AE) |
| FIRM Date | - | Effective March 16, 2016 |
| Primary Hazard | - | Chelsea Creek / Island End River flooding |
| Insurance | - | Mandatory in SFHA for federal mortgages |
Highlighted rows indicate differences between cities.
Boston FAQ
Is my Boston property in a flood zone?
Check FEMA's Flood Map Service Center or contact Boston ISD for a flood zone determination. Approximately 10% of Boston is in a Special Flood Hazard Area, primarily in East Boston, the waterfront, and low-lying areas near the Charles River.
What are Boston's flood zone building requirements?
New construction must elevate the lowest floor to the Base Flood Elevation plus 1 foot of freeboard for residential buildings and 2 feet for critical facilities, per Zoning Code Article 25A. Flood-resistant materials must be used below BFE.
Chelsea FAQ
Is my property in a flood zone in Chelsea?
Chelsea has significant flood risk: 15% of the city is currently in SFHA (Zone AE near Chelsea Creek and Island End River); projected to reach 34% by 2081. FEMA revised Flood Insurance Rate Maps effective March 16, 2016. NFIP participation required; flood insurance mandatory for federally backed...
Do I need flood insurance in Chelsea?
SFHA Coverage: 15% of city (Zone AE). FIRM Date: Effective March 16, 2016. Primary Hazard: Chelsea Creek / Island End River flooding. Insurance: Mandatory in SFHA for federal mortgages.
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