Harris County's flood maps just got redrawn. The Woodlands is still on maps from 2014.
In February, FEMA released draft flood maps for Harris County — the first countywide update since 2007. They carry no regulatory weight yet. Effective maps are estimated for 2028 or 2029. But they are public, they are address-searchable, and they are the clearest picture anyone has had in almost twenty years of where water actually goes.
The maps governing The Woodlands date to August 2014. That matters for a specific reason: NOAA did not update its Texas rainfall statistics until 2018, and Harvey was 2017. The Woodlands is operating on maps drawn before the rainfall math changed and before the storm that changed it.
The updated rainfall data — Atlas 14 — put the 100-year, 24-hour rainfall figure roughly a third higher than the numbers the older maps were built on. Harris County's preliminary guidance suggests floodplains expand somewhere between 50 and 100 percent under the new modeling. The modeling itself is also better: instead of treating channels in isolation, it simulates how water actually moves across flat ground, which is what flat ground does.
The number worth holding onto: roughly 70 percent of homes that flooded during Harvey were outside the mapped high-risk zone. The maps were not wrong about the zone. They were silent about everything else.
It is not all expansion. Some parts of Harris County come out of the floodplain in the draft maps, the result of channel widening and detention basins built over the last two decades. That work moved real risk. The maps are finally catching up to it in both directions.
If you are buying in Harris County: the draft maps are public and you can search an address. A property sitting in Zone X today may sit inside an expanded floodplain on the draft. That does not change anything at closing, but it may change your insurance while you own the home. Price it, and call an insurance agent before your option period ends — not after.
If you are buying in Montgomery County: there is no draft map to check. You have a 2014 map and reasonable inference. Ask about street-level flooding history. Ask the neighbors, who will tell you things a disclosure will not. Get an elevation certificate.
If you already own: flood risk and flood zone were never the same thing. Roughly 82 percent of Harris County housing carries no flood insurance, and nationally about one in three federal flood insurance claims comes from outside a high-risk zone. Those two facts sit badly together.
We will update this once Montgomery County releases its own timeline.
Flood risk and flood zone were never the same thing. In The Woodlands, the governing maps were drawn before the storm that rewrote the math.
Draft flood maps are preliminary and carry no regulatory effect until adopted. These are general observations from our transaction experience, not insurance, legal, or engineering advice. Verify flood zone status and insurance implications directly with FEMA, your county, and a licensed insurance agent for your specific property.