Local Permitting & Improvement Requirements

All new development and redevelopment projects in Winchester’s 100-year floodplain are regulated by the:

  • National Flood Insurance Program (NFIP);
  • Winchester’s Floodplain Overlay District, which is part of the town’s zoning bylaw (PDF); and
  • Massachusetts Wetlands Protection Act, which is administered locally by the Winchester Conservation Commission, as well as the local Winchester Wetlands By-law.

This list is not exhaustive. Check with individual departments requiring permitting requirements.

Before and after development diagram

Decreasing Flood Threats

These floodplain management requirements are designed to prevent new development from increasing the flood threat and to protect new and existing buildings from anticipated flood events.

Property owners should consult with the Winchester Building Department and Conservation Agent before beginning any project that will alter the 100-year floodplain; this includes the building of any new structures or additions, and the alteration of grades in the floodplain. Illegal development in the floodplain should be reported to the Building Department.

National “Substantial Improvement” Requirements

The NFIP defines “substantial improvement” as any rehabilitation, addition, or other improvement to a building when the cost of the improvement equals or exceeds 50% of the market value of the building before the start of construction . The term includes buildings that have sustained “substantial damage”, defined as damage of any origin sustained by a building when the cost of restoring the building to its pre-damaged condition would equal or exceed 50% of the market value of the building before the damage occurred.

Structures meeting the definition of “substantial improvement” or “substantial damage” must meet the same floodplain construction requirements as a new building. This means that they are required to elevate the lowest floor, including the basement and certain utility systems, 1 foot above the base-flood elevation, which is the elevation to which the 100-year flood is predicted to rise.

Elevation Certificates

The NFIP requires communities to obtain documentation of the elevation of the lowest floor (including basement) of all new and substantially improved structures and to maintain a record of all such information in all identified Special Flood Hazard Areas (SFHAs). This elevation information is required to show that buildings are properly elevated in conformance with the floodplain management requirements, i.e. the lowest floor is at least 1 foot above the base flood (100-year) flood elevation, and for property owners to obtain flood insurance.

The Town of Winchester uses the Elevation Certificate form developed by FEMA to fulfill this requirement. The form can be found here.  The certification must be signed and stamped by a registered professional land surveyor, engineer, or architect authorized by law to certify elevation information. All elevation certificates are kept on file at the Winchester Engineering Department.