Neighborhood · Flood Risk
FloodMapsGet a detailed flood report of any Houston property
MAAPnext 2026 Status
Preliminary Maps Released
Updated flood boundaries along Keegans Bayou and Brays Bayou tributaries
Primary FEMA Zones
Harvey Impact
Severe2,200+ FEMA claims filed in 2017
Primary Watershed
Brays Bayou
Keegans Bayou tributary draining southwest Harris County
Est. Flood Insurance Cost
$1,800–$3,800
Based on estimated annual flood insurance premium
Drainage Infrastructure
Keegans Bayou channel improvements
HCFCD-managed channel conveyance and detention upgrades
Many do. A significant portion of Alief properties fall within FEMA Zone AE along Keegans Bayou and Brays Bayou tributaries, requiring flood insurance for federally backed mortgages. Even Zone X properties face elevated risk from flash flooding due to older drainage infrastructure and dense development. Annual premiums range $1,800–$3,800 depending on elevation and zone designation.
Yes. FEMA’s MAAPnext 2026 preliminary maps have been released for the Brays Bayou watershed covering Alief. Updated flood boundaries along Keegans Bayou reflect new rainfall models and channel capacity data. Some properties previously in Zone X are being reclassified into the Special Flood Hazard Area. Property owners should review draft maps before final adoption triggers new insurance requirements.
Severely. Alief recorded over 2,200 FEMA flood damage claims after Harvey in August 2017, with Keegans Bayou and Brays Bayou tributaries overflowing into residential areas. Inundation depths of 2–4 feet were widespread across the neighborhood’s dense subdivisions. Older drainage infrastructure — much of it built in the 1970s — was completely overwhelmed by the storm’s 40+ inches of rainfall.
Volume and aging infrastructure. Alief is one of Houston’s most densely populated areas with high impervious surface coverage from wall-to-wall development. Drainage systems built in the 1970s were designed for far less runoff than today’s built environment produces. Keegans Bayou channel improvements are underway, but capacity still falls short during flash flooding events above 2 inches per hour.
It depends on the specific lot. Alief’s flood risk varies by proximity to Keegans Bayou and local drainage capacity — some blocks flood routinely while others stay dry. With high real estate turnover and affordable prices, a FloodMaps report showing your exact elevation, FEMA zone, Harvey damage records, and AI risk score is essential before purchasing.
Alief is one of Houston’s most densely populated neighborhoods in southwest Harris County, situated along the Brays Bayou watershed with direct exposure to Keegans Bayou flooding. With properties spanning FEMA Zones AE, X, and X (Shaded), and MAAPnext 2026 preliminary maps reshaping flood boundaries, property-level flood analysis is essential for buyers navigating this high-turnover real estate market.
FloodMaps provides address-level flood risk reports for every property in Alief, combining FEMA flood zone designations, USGS 3DEP LiDAR elevation data, Keegans Bayou and Brays Bayou proximity analysis, HCFCD channel improvement project data, Hurricane Harvey damage records, subsidence monitoring, and live Houston 311 flood reports. Each report includes base flood elevation comparisons, freeboard calculations, and an AI-powered risk summary.
If you’re considering purchasing a home in Alief, evaluating flood insurance requirements, or want to understand how Keegans Bayou channel improvements and MAAPnext map updates affect your specific property, search your address for a comprehensive flood risk analysis — including drainage infrastructure data and risk factors that traditional FEMA flood maps don’t capture.