When heavy rain moves into Harris County, conditions can change quickly and may vary greatly from one neighborhood to another. The Harris County Flood Warning System gives residents a way to monitor rainfall and water levels in bayous, creeks, and tributaries as conditions develop.

The system provides real-time information from gages across Harris County and the surrounding region, helping residents better understand what is happening near their homes, workplaces and travel routes.

The Harris County Flood Control District operates the Flood Warning System to measure rainfall and monitor stream elevations on a real-time basis.

How to Use the Flood Warning System

1. Start with the interactive map

Visit HarrisCountyFWS.org to open the Flood Warning System map. Residents can also sign up to receive FWS alerts by text message or email.  

Use the address search to locate your home, workplace, or another location you frequently visit, such as a relative’s home. 

Once you find your area, identify nearby gage stations along local bayous, creeks, or tributaries.

Because rainfall can vary significantly across Harris County, checking the gages closest to you can provide a more useful picture of local conditions than looking only at countywide weather information.

2. Check rainfall totals

Select the rainfall information on the map to see how much rain has been recorded at individual gage stations.

Rainfall sensors transmit data as rain is recorded, allowing users to compare rainfall totals across different parts of the county.

This can help answer questions such as:

• How much rain has fallen near my neighborhood?
• Is another part of Harris County receiving heavier rainfall?
• Has rainfall continued to increase over the past several hours?

3. Monitor water levels

The system also tracks water surface elevations in streams throughout the county. By selecting a gage, residents can see whether a nearby bayou or creek is rising, holding steady, or beginning to recede.

During heavy rain, checking both rainfall totals and water levels can provide a more complete picture of local conditions. Rising water levels may indicate that runoff is continuing to enter a channel, while falling levels can show that conditions are beginning to recede.

Because conditions can change quickly, residents should continue monitoring rainfall and water levels throughout a rain event.

4 . Check historical information

The Flood Warning System also provides information about historical rainfall and flooding events.

Historical data can help residents better understand how rainfall has affected their area during previous storms and how conditions during a current event compare with past events.

How the System Works

The system relies on 201 Flood Control District gage stations strategically located throughout Harris County streams and their tributaries. However, in total, it displays information from more than 350 gage stations across the region, including gages operated by partner agencies.

Each station contains sensors that transmit important information during heavy rainfall and tropical weather events. Some stations also measure wind speed and direction, atmospheric pressure, air temperature, and relative humidity.

That information moves through a network of repeaters located throughout the region before being relayed to primary and backup base stations. Flood Control District staff and automated systems continuously monitor incoming information to help maintain the accuracy and reliability of the system.

The Flood Warning System also incorporates information from partner agencies outside the Flood Control District. 

Together, this information is used by residents, the media, the National Weather Service, emergency management agencies, and the Flood Control District to monitor changing conditions and assess flood risk across the region. 

Why It Matters

The Flood Warning System began in 1982 with 13 gage stations. Following Hurricane Alicia in 1983, the system expanded as the need for additional rainfall and stream elevation information became clear.

Today, the system provides information that can help residents and emergency managers make informed decisions during periods of heavy rain and flooding.

The Flood Control District also uses the information after flood events to help estimate the extent and depth of flooding along streams and the number of structures that may have been impacted.

Without a system like this, residents and emergency officials would have much less real-time information about how rainfall and water levels are changing across Harris County.

Explore the Flood Warning System

Visit HarrisCountyFWS.org before the next rain event. Explore the map, find the gages nearest you, and sign up for text or email alerts so you can stay informed as conditions change.