Renovations in a Floodplain and Floodway and the Substantial Improvement Rule
What is a floodway?
The channel of a river or stream and the parts of the floodplain adjoining
the channel that is reasonably required to efficiently carry and discharge
the flood water or flood flow of a river or stream.
What is a floodplain?
The area adjoining a river or stream that has been or may be covered by
the 100-year flood map.
If you are located in a floodplain or a floodway and are planning on renovations
you need to be aware of some important rules. Based upon where the structure
is located and when it was built certain rules will apply. These rules
can have a major impact on your property. In both the floodway and flood
plain the Substantial Improvement rule applies. Improvements are deemed
to be “substantial” if the cost of improvements exceeds 50
percent of the market value of the building. The cost of improvements
usually includes the market value for all materials and labor, even if
the out-of-pocket expenditures are less (i.e the owner or some volunteers complete some of the labor). The cost of
improvements generally does not include the cost of repairs required to
remedy health, safety, and sanitary code violations.
If your home or building is located in a floodway and substantial improvements
are required to repair the building then the building must be removed.
If your home is in a floodplain what you are able to do will be affected
by when the home was constructed. Was it built (or substantially improved)
after the effective date of the community’s first Flood Insurance
Rate Map (FIRM))? This is the date on which your community began regulating
floodplain development. Any post-FIRM structures should already be in
compliance with floodplain development standards. Any subsequent improvements
must maintain compliance with the standards that were in effect when the
building was built. Renovations, repairs, or additions to post-FIRM structures
are regulated as new construction.
A post-FIRM home that was in full compliance at the time of construction
may still not meet current floodplain development standards. This can
result from a map revision that expands the regulated floodplain area
and/or increases the calculated height of the 100-year flood (Base Flood
Elevation). It can also result from enactment of stricter standards for
The buildings codes currently require flood protection to a level two feet
above the Base Flood Elevation. Any substantial improvements to a post-FIRM
structure must meet the requirements of the current ordinance, which may
require elevation of the entire structure.
Some structures were built prior to enactment of floodplain development
standards and were constructed without taking the flood hazard into account.
The requirements for modifications to these structures depend on the magnitude
of the proposed changes (i.e. is it a substantial improvement). If it is a substantial improvement then
the home will like need to be renovated to current flood standards. This
may require raising the home 2 feet above Base Flood Elevation or other
measures such as filling in lower levels or basements.
If you have questions about the legal implications of repair or renovations
please do not hesitate to
call the Finkel Law Firm.