Floodplain Overlay Districts
All communities that participate in the National Flood Insurance Program (NFIP) are required to enforce minimum NFIP regulations through the adoption of a Floodplain Overlay District. The Floodplain Overlay District must encompass the FEMA Special Flood Hazard Area (SFHA), also known as the 1% chance or the 100-year flood zone. The Massachusetts Flood Hazard Management Program has developed a model Floodplain Bylaw/Ordinance that identifies required and recommended language. The model includes minimum state requirements (building code, wetlands and others) that apply in the SFHA.
Limitations and restrictions associated with FEMA flood maps and the state building code can make it difficult to craft regulations that will reduce flooding and flood damage. Despite the challenges, many communities have gone beyond minimum federal and state requirements to reduce their vulnerability to flooding. Strategies include expanding overlay districts beyond the SFHA, prohibiting construction in the SFHA, requiring special permits for construction, protecting flood storage, and more. As seas rise and precipitation increases, these are important tools for protecting communities and overcoming the current limitations in FEMA flood maps and building code regulations.
This page provides short summaries of key features of regulations based on desktop review. Links to the regulations are provided below. Conduct careful review when considering adopting new language. The resources included do not constitute legal advice. Municipalities should consult legal counsel when adopting new bylaws, ordinances, and policies.
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Language Examples
Additional Resources
Strategies to Strengthen Floodplain Overlay District Requirements
A number of coastal communities have adopted language that encourages elevating buildings or utilities in the FEMA 1% flood zones to, or above, base flood elevation.
- Winthrop allows existing buildings in the floodplain to exceed zoning height limits to elevate up to 3 feet beyond building code requirements.(17.16.020 Ordinance of 07-19-2022 (1) | Code of Ordinances | Winthrop, MA | Municode Library)
- Hull allows new and existing structures to exceed zoning height limits, by Special Permit, to elevate up to 4 feet. (Hull 4.10.5.1.a1; bi)
- Scituate allows existing structures to elevate to achieve base flood to a maximum height of 50 feet. (Scituate 200 Section 100)
- Dennis allows existing structures to exceed height limits for up to 3 feet of freeboard. (Dennis 6.7)
- Dennis and Nantucket measure building height from base flood rather than average mean grade in FEMA 1% flood zones. (Dennis 6.7 and Nantucket 139.17.C.7)
- Hull and Winthrop allow encroachment into setbacks to facilitate elevation of utilities including heating units, water heater and hot water storage, electrical panel, washer and dryer. (17.16.020 Ordinance of 07-19-2022 (1) | Code of Ordinances | Winthrop, MA | Municode Library)