Flooding in San Marcos

Flooding in our city is caused by three sources: the San Marcos River, the Blanco River, and Purgatory Creek. Floodwaters can cover many blocks up to three or four feet deep.

Flooding in all three areas can come with little warning. A flood in October of 1998 covered streets within 30 minutes of forming. In November of 2001 the Blanco River flooded within an hour after a thunderstorm started. Floods are also dangerous. Even though they appear to move slowly (three feet per second), a flood two feet deep can knock a man off his feet and float a car.

Your property may be high enough that it was not flooded recently. However, it can still be flooded in the future because the next flood could be worse. If you are in the floodplain, the odds are that someday your property will be damaged.

Notice to Residents in the Special Flood Hazard Area

Notice to Lending Institutions and Real Estate and Insurance Agents

San Marcos has a number of low water crossings and creeks that are susceptible to flooding during heavy rains, posing a threat to safety and property. Over 341 acres within San Marcos are designated as being in a Special Flood Hazard Area (SFHA). Heavy rains in 1998 and 2001 caused flooding and damage to buildings in these areas. However, your property need not be located in the SFHA to sustain flood damage. When drainage courses or storm drains become clogged, they will backup and overflow causing property damage to even upland structures.

The City can provide information about the location of your property in relation to the flood zone, Elevation Certificates, flood maps, flood safety and flood preparedness information. To help you learn more about the flood hazard in San Marcos, and what you can do about it, the City has available online more information to assist you in being prepared for flooding in San Marcos. Please learn more about Flood Insurance because homeowner’s insurance policies do not cover you for flood damage. You can also learn more about What You Can Do to keep your life and property safe in a flood. Also, learn about the Floodplain and Regulations that help protect you from losses in a flood situation.

To help you get an idea of where the highest risk of flooding in San Marcos is, excerpts from the National Flood Insurance Rate Map are also available online.