Learn about the data sources used to determine flood damage estimates.
The data used to calculate annual flood damage costs primarily comes from the First Street Foundation Flood Model and the United States Army Corps of Engineers (USACE), with additional property data, including property value, provided by ComeHome from HouseCanary, a leading source for property value data, and from Lightbox.
Data sources used
The annual flood damage cost estimates refer to how much, on average, a property-owner could expect to pay in repair costs from flood damage to their building in a given year. It is calculated based on a property’s flood risks, the likelihoods and depths of flooding projected for a building and building characteristics, such as property type, elevation, materials, building value.
- The estimated property value data comes from ComeHome by HouseCanary’s automated valuation model (AVM). HouseCanary is a leading source for property values and related data. Where AVMs are not available from ComeHome, they are estimated using the building characteristics through a peer-reviewed methodology developed by First Street Foundation.
- The estimated building structure value and building characteristics for each property comes from the National Structures Inventory (NSI) database or Lightbox, a leading provider of commercial real estate data.
- The historical data on flood damage costs comes from the United States Army Corps of Engineers (USACE). The USACE data analyzes the relationship between depth of flooding and the amount of damage caused, based on historical records from FEMA insurance claims.
- The projected depth and likelihood of flooding from the First Street Foundation’s Flood Model.
Additionally, fluvial (riverine) and coastal depth-damage curves from the United States Army Corps of Engineers (USACE) are applied to First Street Foundation’s Flood Model. Using the same methods as the USACE, First Street Foundation has created a separate peer-reviewed pluvial (precipitation) damage curve to fully account for all types of flood risks.
Please note, the flood risk damage estimates only include potential structural damage to homes, and do not include additional costs to homeowners of replacing the contents of their home, or potential overhead costs associated with storage of property, finding temporary shelter, and other interim costs that may be included in NFIP premium calculations.