Houston's New FEMA Flood Maps: Where the Update Actually Stands (September 2026)
Houston's New FEMA Flood Maps: Where the Update Actually Stands (September 2026)
Harris County's flood maps are being redrawn for the first time since 2007. The draft maps have been public since February - but the official process is earlier than most people think, and the timeline is longer than anyone first said. This post tracks where the update stands, what happens next, and what it means for your address. We update it as the process moves.
Where the Maps Stand Right Now
As of September 2026, Houston's new flood maps are drafts - viewable by anyone, but not open for formal comment or appeal, and not usable for insurance or regulatory decisions. That's the official word from the Harris County Flood Control District's MAAPnext site.
How we got here: FEMA and the Flood Control District kicked off MAAPnext - the Modeling, Assessment, and Awareness Project - in 2019, after Harvey exposed how badly the 2007 maps understated risk. In the first week of February 2026, FEMA handed draft map data to the county's 34 floodplain administrators for technical review, and the data went public through an interactive dashboard shortly after.
The key distinction most coverage misses: what you can view today is a draft. The document that actually starts the regulatory clock - FEMA's Preliminary Flood Insurance Rate Maps - is still working through federal review. Only after those are released does the formal public review and 90-day appeal period begin.
| Stage | Status (Sept 2026) | What it means for you |
|---|---|---|
| Draft maps (MAAPnext) | HERE NOW - public since February 2026 | Informational only. Good for planning, useless for appeals or insurance decisions. |
| Preliminary FIRMs | Pending - in FEMA federal review | The official starting gun. Triggers the formal comment and appeal period. |
| 90-day appeal period | Not open yet | Your formal window to challenge a zone with data (elevation certificates matter here). |
| Letter of Final Determination | Not issued | FEMA finalizes the maps after resolving appeals. |
| Maps become effective | Estimated around 2028 | Zones become law. Insurance requirements change for reclassified properties. |
What the Draft Maps Already Tell Us
Draft or not, the direction is clear: Houston's mapped flood risk roughly doubles. The current maps place about 184,800 county properties in the regulatory 100-year floodplain. The draft maps put roughly 345,400 in it.
Two technical shifts drive most of the change. NOAA's Atlas 14 raised the official 100-year, 24-hour rainfall benchmark for Houston from 13.2 inches to 17 inches - what used to count as an extreme storm is now the design storm. And for the first time, the models track how water ponds in streets and flows through neighborhoods, not just how bayous rise. We walk through the property-level implications in our homeowner's guide to the 2026 changes.
The Timeline, Honestly
When this post first ran in February, the working assumption was final maps around 2027. The county's own reported estimate is now around 2028 - and even that assumes the preliminary FIRMs, the appeal period, and the final determination all move without slipping. Federal map processes slip. Treat 2028 as the current best guess, not a date on the calendar.
The slow timeline cuts both ways. You have more time to prepare - but the draft maps already show where risk is heading, and insurance pricing rewards acting before reclassification becomes official, not after.
The Next Curveball: Atlas 15
Even before the new maps become law, the science under them is being superseded. NOAA is building Atlas 15, the successor to the Atlas 14 rainfall statistics that MAAPnext is built on.
Atlas 15 is the first national precipitation atlas to account for future climate trends, projecting rainfall frequency estimates through the year 2100 instead of assuming the past predicts the future. Preliminary estimates for the contiguous U.S. are expected this month - September 2026 - after a public review of the Montana pilot. Nobody should be surprised if Atlas 15 pushes Houston's design rainfall numbers higher again, and starts the argument over whether the 2028 maps are already out of date.
What You Can Do While the Process Grinds
- Look up your address now. A FloodMaps report shows your current FEMA zone and the draft MAAPnext zone side by side, plus ground elevation and whether Harvey damage was recorded at your address. If you're being reclassified, better to know two years early than two months late.
- Buy flood insurance before the maps go effective. If the draft maps move you into a high-risk zone, a policy bought now locks in newly-mapped pricing with capped annual increases. Our homeowner's guide has the details.
- Get an elevation certificate if the draft map looks wrong. The models estimate your home's height from aerial data. A surveyor's certificate can prove you sit higher - and when the appeal period finally opens, it's the document that wins appeals.
- Remember the maps are a floor, not a ceiling. A Texas A&M model trained on actual flood insurance claims estimates about 389,500 Harris County properties face 100-year-level risk - more than even the draft maps show. We broke down why every model tells a different story.
Houston has waited 19 years for this redraw - and the wait says as much as the maps do. For the full history of how the city got here, read our Harvey anniversary retrospective. The maps are coming. The water won't wait for them.
Quick Answers
When will Houston's new FEMA flood maps take effect? Not before 2028, by the county's own reported estimate. The maps are currently drafts; FEMA's Preliminary FIRMs are still in federal review, and the 90-day appeal period that follows them has not started.
Can I appeal my flood zone under the new maps yet? No. The draft MAAPnext maps are informational only and not open for formal comments or appeals. The appeal window opens only after FEMA releases the Preliminary Flood Insurance Rate Maps.
What do Houston's draft flood maps show? Roughly 345,400 Harris County properties in the 100-year floodplain - nearly double the 184,800 on the current 2007 maps - driven by NOAA's higher Atlas 14 rainfall benchmark and new modeling of street-level ponding.
What is NOAA Atlas 15? The successor to the Atlas 14 rainfall statistics, now in development. It's the first U.S. precipitation atlas to factor in future climate trends through 2100; preliminary nationwide estimates are expected in September 2026.