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
May 04 2026
Yesterday
May 03 2026
Six Month
Nov 04 2025
One Year
May 04 2025
Ten Day
Average
Historical
Monthly Average
Difference From
Historical Average
San Antonio Pool (J-17) 639.4 639.4 626.7 629.6 637.0 664.5 -25.1
Today
May 04 2026
Yesterday
May 03 2026
Six Month
Nov 04 2025
One Year
May 04 2025
Ten Day
Average
Historical
Monthly Average
Difference From
Historical Average
Uvalde Pool (J-27)            834.8 834.7 839.1 825.4 834.5 866.0 -31.2



   Springs Historic Daily Mean Springflow

Today
May 04 2026
Yesterday
May 03 2026
Six Month
Nov 04 2025
One Year
May 04 2025
Ten Day
Average
Historical
Monthly Average
Difference From
Historical Average
Comal Springs            140 140 63 68 130 290 -150
Today
May 04 2026
Yesterday
May 03 2026
Six Month
Nov 04 2025
One Year
May 04 2025
Ten Day
Average
Historical
Monthly Average
Difference From
Historical Average
San Marcos Springs    85 85 87 86 84 180 -95

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)