If you're buying or renting a home in Houston, two flood questions matter before you sign anything: what flood zone the address is in, and whether the house has actually flooded. They aren't the same question, and no single map answers both. This guide walks through the free official tools that answer each one for a specific Houston or Harris County address, what the zone letters mean, and what the seller or landlord has to tell you in Texas. Everything here was checked against FEMA, the Harris County Flood Control District, the Texas Real Estate Commission and the Texas Property Code on October 11, 2026.
TL;DR
- Your official flood zone comes from FEMA's Flood Map Service Center. Type in the address and it shows the effective flood map for that spot.
- Zones starting with A or V are high-risk. If you're in one and your mortgage is federally backed, your lender will require flood insurance. Shaded X is moderate risk and unshaded X is lower risk, but neither means no risk.
- Harris County's new MAAPnext maps are still drafts as of October 11, 2026. They're useful for awareness, but they can't be used for insurance or regulatory decisions yet.
- A flood zone isn't a flood history. For history, read the seller's disclosure, ask about past flood claims and FEMA or SBA aid, and check the Harris County Flood Control District's tools.
- Texas landlords have to give tenants a written flood notice, including whether the dwelling flooded in the last five years.
Step 1: Find the official FEMA flood zone for the address
FEMA's Flood Map Service Center is, in FEMA's words, "the official public source for flood hazard information" produced for the National Flood Insurance Program (NFIP). It's free and doesn't need an account.
- Open the Map Service Center and enter the street address in the "Looking for a Flood Map?" search box. You can also enter a place name or latitude and longitude.
- The results page shows the effective flood map for that location, with the flood zone shaded on the map.
- Use the "Print" option to make a FIRMette, a printable section of the Flood Insurance Rate Map (FIRM) for that address. It's worth saving a copy with your house-hunting notes.
- Write down the FIRM panel number shown in the results. According to the Map Service Center FAQ, you can search that panel number in "Search All Products" to find the full panel, older maps, and any Letters of Map Change issued for the area.
FEMA says maps are updated over time and anything you print "may change or become superseded by new maps," so check again close to closing. As of October 11, 2026, the Map Service Center also posted that it will be down starting Saturday, October 17, for a database migration, with service expected back on Sunday, October 18.
Step 2: Read the zone letter correctly
FEMA's FloodSmart site explains the zones on its flood zone page. In plain terms:
- Zones A, AE, AH, AO, AR and A99: High-risk flood areas, also called special flood hazard areas. In communities that take part in the NFIP, flood insurance is mandatory if your mortgage is government-backed.
- Zones V and VE: High-risk coastal areas with the added hazard of storm waves.
- Zone B and shaded Zone X: Moderate flood hazard, usually the area between the 100-year and 500-year flood limits.
- Zone C and unshaded Zone X: Minimal flood hazard, usually shown as above the 500-year flood level. FloodSmart notes these areas can still have ponding and local drainage problems.
- Zone D: Possible flood hazards, but no analysis has been done, so the risk is undetermined.
The "100-year" label confuses a lot of buyers. It doesn't mean a flood once a century. The Harris County Flood Control District's Flood Education Mapping Tool explains that a structure in a 1% (100-year) floodplain has at least a 1% chance of flooding in any given year and at least a 26% chance over 30 years. In a 0.2% (500-year) floodplain, it's at least a 0.2% chance a year and at least 6% over 30 years.
Being outside the high-risk zones doesn't make a house safe from flooding. FloodSmart's flood risk page says 29% of NFIP flood insurance claims from 2014 to 2024 came from areas outside current high-risk flood areas. It also notes that most homeowners and renters insurance policies don't cover flood damage.
Step 3: Look at Harris County's draft MAAPnext maps
Harris County's flood maps are being redrawn. The Harris County Flood Control District and FEMA call the project MAAPnext, and the District describes it as the most comprehensive update since 2007, built on NOAA's 2018 Atlas 14 rainfall study, 2018 LiDAR elevation data and newer flood modeling.
As of October 11, 2026, the MAAPnext site lists the map status as draft. The District says draft maps:
- are shared for informational and educational purposes only
- aren't final and can't be used for insurance or regulatory decisions
- aren't open for public comment or appeals yet
FEMA is expected to release Preliminary Flood Insurance Rate Maps after its federal review, and then start a formal public review and appeal period. Only once the new maps are finalized do they become the official FIRMs used for insurance and permitting.
Why look at drafts at all? The District says the new maps "may affect which properties are required to carry flood insurance once they become effective." If you're buying a home you plan to keep for years, it's worth knowing whether the draft maps show the address differently from today's effective map. You can enter an address in the MAAPnext Navigator, the site's interactive map.
Step 4: Check how water actually behaves around the house
FEMA zones mostly describe flooding from bayous, creeks and the coast. Harris County gets more than that. MAAPnext describes three kinds of flooding here: riverine flooding when bayous and creeks overflow, community flooding when heavy rain overwhelms storm sewers and roadside ditches, and coastal flooding from storm-driven tides. The District also says that, on average, a major flood happens somewhere in Harris County every two years.
Two free county tools help fill in the picture for a specific address:
- Flood Education Mapping Tool (FEMT): Enter an address to see the floodway, the 100-year and 500-year floodplains, the coastal floodplain, nearby channels with their District ID numbers, and ponding areas. Ponding is shaded red, and darker red means deeper water collecting on streets or land.
- Harris County Flood Warning System: An interactive map with rainfall data, water levels and channel status at gauges across the county, plus an address search. It's also a quick way to see which bayou or creek gauge sits closest to a home.
The District also makes a point that surprises some buyers. Hurricane Harvey wasn't the worst flood for every neighborhood, and the 100-year floodplain doesn't represent Harvey or any single storm. A house can have flooded in Harvey and sit outside a high-risk zone, or sit inside one and have stayed dry in Harvey. That's exactly why the zone and the history need separate checks.
Step 5: Ask for the flood history in writing
Flood history comes from people and paperwork, not maps.
The seller's disclosure
The Texas Real Estate Commission's Seller's Disclosure Notice (TREC No. OP-H) has a section just for flooding. It asks whether the seller is aware of:
- present flood insurance coverage
- previous flooding from a reservoir breach or a controlled or emergency release of water from a reservoir
- previous water getting into a structure on the property from a natural flood event
- the property being wholly or partly in a 100-year floodplain, a 500-year floodplain, a floodway, a flood pool or a reservoir
It also asks two yes-or-no questions: whether the seller has ever filed a flood damage claim with any insurer, including the NFIP, and whether the seller has ever received help from FEMA or the U.S. Small Business Administration (SBA) for flood damage to the property. Read those answers closely, and ask follow-up questions in writing if anything is marked yes or left blank. If your contract includes an option period, that's the time to dig in. Our guide to option money in Texas explains how that window works.
The elevation certificate
An elevation certificate shows how high a building sits compared with how high local floodwaters are expected to get. FloodSmart's elevation certificate page says a home may already have one on file with the local floodplain manager. If it doesn't, a land surveyor, engineer or architect can complete one. Most homeowners don't need one to buy flood insurance, but owners in Zones A and V may, and a certificate can help identify discounts.
Past claims in the area
FloodSmart's historical NFIP claims tool lets you pick Texas and a county and see NFIP claims paid over time, going back to 1980. It covers only claims the NFIP paid, not private insurance or uninsured damage, and it's county-level, not house-level. It's still a useful reminder: MAAPnext notes that more NFIP flood insurance money has been paid in Harris County than in any other NFIP community.
Renting? Texas landlords owe you a flood notice
Under Texas Property Code Section 92.0135, a landlord has to give a tenant a written notice saying whether the landlord is or isn't aware that the dwelling is in a 100-year floodplain. If neither box is checked, the notice tells you to assume it is. If the landlord knows flooding damaged any part of the dwelling at least once in the five years before the lease starts, the landlord must give a second notice saying so.
The notices have to be in the lease, in an addendum, or in a separate document given at or before signing, and both sides sign it. If a landlord doesn't comply and a tenant then has a substantial flood loss to their belongings (repairs or replacement costing at least 50% of the items' market value), the tenant can end the lease with written notice within 30 days of the loss. The notice isn't required for leases shorter than 30 days or for short pre-closing or post-closing occupancy of up to 90 days under a sale contract. If you're working with a leasing agent, our guide to how Houston realtors help with rentals covers what else to ask.
FAQ
How do I find the flood zone for a Houston address?
Enter the address on FEMA's Flood Map Service Center. The results show the effective flood map and zone for that location, and you can print a FIRMette for your records.
What does Zone X mean in Houston?
Shaded Zone X is a moderate flood hazard area, usually between the 100-year and 500-year flood limits. Unshaded Zone X is minimal hazard, usually above the 500-year level. The federal flood insurance requirement for government-backed mortgages applies to the high-risk A and V zones, but Zone X homes can still flood.
Are the new Harris County flood maps in effect?
Not as of October 11, 2026. The MAAPnext maps are drafts, and the Flood Control District says they can't be used for insurance or regulatory decisions. FEMA is expected to issue preliminary maps first and then hold a public review and appeal period.
Does a 100-year floodplain mean the house floods once every 100 years?
No. It means at least a 1% chance of flooding in any given year, which the Harris County Flood Control District says works out to at least a 26% chance over 30 years.
How can I tell if a house flooded in Harvey?
Start with the seller's disclosure, which asks about previous flood water in the structure, past flood claims and FEMA or SBA flood assistance. Ask the seller directly and in writing, and have your inspector look for signs of past water damage.
Do I need flood insurance if I'm outside the high-risk zone?
Your lender may not require it, but FEMA recommends it. FloodSmart reports that 29% of NFIP claims from 2014 to 2024 came from outside high-risk areas, and most homeowners policies exclude flood.
Can a flood zone be changed?
FEMA can revise a flood zone designation for a property through a Letter of Map Amendment or Letter of Map Revision, which you can request through FEMA's online Letter of Map Change application.
One last thing
Check the zone and the history before you're attached to a house, then check the zone again close to closing. Pair what you learn with a thorough inspection; our guides to what happens during a Houston home inspection and what a home inspection costs in Houston cover that step. When you're ready, browse Houston homes for sale or talk to our team about a specific address.