Houston's flood data,
explained.

Why Floodfolio exists

Greater Houston has one of the most complex flood environments in the United States. The metro sits on flat coastal plain, crossed by bayou systems that overflow during intense rainfall events — which happen more frequently here than almost anywhere else in the country. Five named storms caused significant residential flooding between 2015 and 2019 alone: Memorial Day 2015, Tax Day 2016, Harvey 2017, Imelda 2019, and others before and since.

When Hurricane Harvey made landfall in August 2017, more than 154,000 structures flooded across the greater Houston area — tens of thousands of which were in areas FEMA had classified as lower-risk Zone X. The official flood map had not caught up with actual flood behavior.

FEMA's own flood map viewer shows zone designations but doesn't explain what they mean, doesn't show your elevation relative to the flood line, and doesn't show how your neighborhood has actually performed during real storms. Buyers typically rely on a realtor's summary or skip the research entirely. Floodfolio was built to fill that gap.

What a Floodfolio report includes

• 1FEMA flood zone — the official designation for that parcel: Zone AE (high risk), Zone X Shaded (moderate), Zone X (minimal), or other classifications. Pulled directly from the FEMA National Flood Hazard Layer.
• 2Ground elevation — the estimated elevation of the property in feet above sea level, derived from USGS LiDAR surveys at 1-meter horizontal resolution.
• 3Base Flood Elevation (BFE) — the water surface height FEMA models for a 1% annual chance flood at that location. This is the official flood benchmark for Zone AE properties.
• 4Freeboard — the gap between ground elevation and BFE. A positive freeboard means the property is above the modeled flood line; negative means below it.
• 5NFIP claim history — the number of federal flood insurance claims filed in that ZIP code, broken down by named storm. Shows how an area has actually performed during real flood events, not just what the map predicts.
• 6Risk score (1–10) — a composite score based on flood zone, freeboard, and claim density, designed to make the data comparable across addresses.

Data sources

Coverage area

Floodfolio covers the five-county Greater Houston service area:

This covers the cities of Houston, Pasadena, Pearland, Sugar Land, Katy, The Woodlands, Conroe, Galveston, League City, Friendswood, Baytown, and surrounding communities.

Disclaimers

Floodfolio reports are informational references compiled from public government records. They are not Standard Flood Hazard Determinations, FEMA Elevation Certificates, or licensed engineering assessments. Reports must not be used in credit, insurance underwriting, employment, or lending decisions.

Elevation estimates carry typical vertical accuracy of ±1–2 ft. FEMA flood zone boundaries may not reflect recent map amendments (LOMAs or LOMRs), local drainage improvements, or subsidence since the last survey. A licensed flood insurance agent or certified floodplain manager (CFM) can advise on coverage for a specific property.

Floodfolio is an independent data aggregation service and is not affiliated with FEMA, USGS, the National Flood Insurance Program, or any government agency.