HomeMy WebLinkAboutInstallation in High Risk Flood Zones (DLNR - Wai Halana, April 2012 ed.)
Photovoltaic Installations in High
Risk Flood Zones
With most families looking for ways to make ends meet in these
hard economic times, many are turning to Photovoltaic (PV) sys-
tems to help reduce soaring household utility expenses. This grow-
ing popularity has taken root in Hawaii and more and more property
owners are installing these systems to their existing homes.
It is important to understand that for on-roof installation of these PV
panels, the cost of the system must be included in “Substantial Im-
provement (SI) calculations” for structures located in a high risk
flood zone. Also known as the “50% Rule”, this often overlooked floodplain management regulation requires the
evaluation of the improvement cost against the market value of the structure. If the improvement cost exceeds
50% or more of the structure’s market value (excluding land value), then it is considered a “Substantial Improve-
ment” and thus the entire structure must comply with current county floodplain management regulations.
In an effort to avoid triggering the Substantial Improvement designation and the subsequent requirement to bring
an existing building into compliance with current codes, property owners may opt to install the PV panels as a
separate free-standing system.
The following policy guidance on free-standing solar/photovoltaic panels was provided by Jennifer Tylander, Pro-
gram Specialist, FEMA Mitigation Directorate, Washington D.C. :
“If free standing solar/photovoltaic panels (outside the footprint of a structure) are proposed in the floodplain, it is
considered development. Since free standing solar/photovoltaic panels are considered development, permits are
required [60.3(a)(1) ]*. In addition, local officials are to review proposed development to assure all necessary per-
mits have been received from those governmental agencies from which approval is required by Federal or State
law [60.3(a)(2)]*. In addition, the local offi-
cial is to determine whether the proposed de-
velopment is reasonably safe from flooding.
If the free-standing solar/photovoltaic panels
are in a flood-prone area, the proposal for
free standing solar/photovoltaic panels should
be reviewed to assure that all such proposals
are consistent with the need to minimize flood
damage. [60.3(a)(4)]*. Ways to minimize
food damage to free-standing solar/
photovoltaic panels include, but are not lim-
ited to, being adequately anchored to prevent
flotation or collapse, constructed with flood
resistant materials below the Base Flood Ele-
vation, and be designed or located such that
floodwater is prevented from entering or ac-
cumulating in the components that are not
flood resistant during flooding events.”
If your existing home is located in a high risk flood zone, be sure to discuss your proposed plans to install a solar/
photovoltaic system with your local floodplain managers. Each county has floodplain management regulations
that may have more stringent than the minimum NFIP regulations. Contact information for local floodplain manag-
ers can be found at: www.hawaiinfip.org
* Title 44, Code of Federal Regulations
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