Aquifer Conditions

One of the tools used to manage the Edwards Aquifer is the EAA Critical Period Management (CPM) Plan. This plan identifies thresholds for groundwater levels and springflows at specific locations. The J-17 Well, Comal Springs, and San Marcos Springs are used to manage the San Antonio Pool, and the J-27 Well is used to manage the Uvalde Pool. Each of these sites collects continous data that provide an overall assessment of the conditions of the Edwards Aquifer. For more information view the Critical Period Management website.

Unless otherwise noted, all data provided are provisional and subject to revision. The EAA assumes no liability for any damages resulting from its use.



   Index Wells Historic Daily High Levels

Today
Oct 19 2025
Yesterday
Oct 18 2025
Six Month
Apr 19 2025
One Year
Oct 19 2024
Ten Day
Average
Historical
Monthly Average
Difference From
Historical Average
San Antonio Pool (J-17) 626.1 625.6 625.4 626.7 626.4 662.4 -36.3
Today
Oct 19 2025
Yesterday
Oct 18 2025
Six Month
Apr 19 2025
One Year
Oct 19 2024
Ten Day
Average
Historical
Monthly Average
Difference From
Historical Average
Uvalde Pool (J-27)            838.4 838.4 823.6 831.7 838.3 866.1 -27.7



   Springs Historic Daily Mean Springflow     (Current day values not available)

Today
Oct 18 2025
Yesterday
Oct 17 2025
Six Month
Apr 19 2025
One Year
Oct 19 2024
Ten Day
Average
Historical
Monthly Average
Difference From
Historical Average
Comal Springs            63 63 55 58 68 271 -208
Today
Oct 18 2025
Yesterday
Oct 17 2025
Six Month
Apr 19 2025
One Year
Oct 19 2024
Ten Day
Average
Historical
Monthly Average
Difference From
Historical Average
San Marcos Springs    88 87 87 89 89 158 -70

More information on springflow measurements available at the USGS Springs Page.




Historical Water Level Chart

The chart below shows all available daily high water elevation values for the Index Wells.

Use the menu in the upper right corner of the chart to download data. Click on the site at the bottom of the chart to hide that site's data.




Historical Springflow Chart

The chart below shows all available daily mean springflow values for the spring systems.

Use the menu in the upper right corner of the chart to download data. Click on the site at the bottom of the chart to hide that site's data.


More information on springflow measurements available at the USGS Springs Page.


Today's Current Water Level Readings

Water level data are critical for EAA’s management of the San Antonio Pool and the Uvalde Pool of the Edwards Aquifer. Measurements are collected continuously every 15 minutes and displayed as water level elevation (WLE) in feet above mean sea level (ft amsl).

All data below are provisional and subject to revision

San Antonio Pool (J-17)

Well Datetime (Local) WLE (ft amsl)

Uvalde Pool (J-27)

Well Datetime (Local) WLE (ft amsl)