Where in Houston are homes in the flood zone?

In Meyerland, one of Houston's most flood-prone neighbourhoods, 43% of the land lies in FEMA's 100-year flood zone. About 1,470 of the neighbourhood's roughly 4,020 mapped buildings sit inside it.

This example covers Meyerland only (City of Houston Super Neighborhood 31, about 10.6 km²), not the whole city.

Meyerland	Value
Share of land in the 100-year flood zone (FEMA AE)	43%
Share of land in the 500-year zone (0.2% annual chance)	14%
Mapped buildings in the neighbourhood	~4,020
Buildings inside the 100-year zone	~1,470

Fewer than 100 of the buildings inside the 100-year zone are tagged as garages, schools, shops or other non-home uses. The rest are houses or untyped buildings, and Meyerland is overwhelmingly residential: 96% of the HCAD parcels loaded are residential.

How this was worked out

• We used the FEMA National Flood Hazard Layer for Harris County and the City of Houston Super Neighborhood boundary for Meyerland.
• Buildings are OpenStreetMap footprints. A building counts as inside the flood zone when its footprint centre falls in Zone AE.
• Harris County Appraisal District (HCAD) parcels were loaded for land use.

Limitation: only 2,000 of Meyerland's 6,243 HCAD parcels could be loaded, mostly in the west, so homes are counted from building footprints rather than parcels. Being in the zone doesn't mean a home's floor is below flood level, because many have been raised.