Flood Risk
The Guadalupe River Floods — Know Your Risk
The Guadalupe River runs through the county and has a history of serious flooding, so buyers should check FEMA flood maps before purchasing.
The Guadalupe River is the county's main waterway. It drains a large Hill Country watershed. Heavy rain upstream can cause fast, dangerous rises in the county — sometimes within hours. The October 1998 flood was the worst on record for the upper Guadalupe River basin — homes along the river from Canyon Lake to Seguin were washed off their foundations and damage approached $750 million.
The San Marcos River and Geronimo and Cibolo creeks also flow through the county and carry flood risk. Before buying near any of these waterways, look up the property on the FEMA Flood Map Service Center at msc.fema.gov. A property in a Special Flood Hazard Area (SFHA) typically requires flood insurance.
Source to confirm: FEMA Flood Map Service Center