Where San Antonio and Austin Get Their Water: Edwards Aquifer and Beyond
Both cities sit on the Edwards Aquifer—a karst limestone formation stretching 8,000 sq mi across central Texas. But their water portfolios differ.
San Antonio (SAWS)
- ~90 % Edwards Aquifer (San Antonio Pool). Permitted withdrawal capped by Edwards Aquifer Authority (EAA) to protect Comal & San Marcos Springs (endangered species habitat).
- ~10 % diversified: Canyon Lake (GBRA contract), Carrizo Aquifer (desalination), recycled water (purple pipe), ASR (Aquifer Storage & Recovery) — 200,000 acre-ft banked underground.
Austin (Austin Water)
- ~70 % Colorado River (Lake Travis, Lake Austin) — surface water rights.
- ~20 % Edwards Aquifer (Barton Springs segment) — limited by Barton Springs/Edwards Aquifer Conservation District.
- ~10 % reclaimed water — irrigation, cooling, toilet flushing (growing).
Key Differences
| Aspect | San Antonio | Austin |
|---|
| Primary source | Edwards Aquifer (groundwater) | Colorado River (surface) |
| Regulator | Edwards Aquifer Authority | TCEQ + Barton Springs District |
| Drought trigger | EAA critical period stages | Lake Travis combined storage |
| Long-term plan | Vista Ridge pipeline (142 mi, Burleson Co. Carrizo) | Water Forward 100-yr plan (conservation, ASR, reuse) |
Both face growth + climate stress. Diversification and conservation are now survival strategies.
Wanderlust World