WaterMark / Jurisdictions / Bexar County, TX (San Antonio)
Bexar County, TX (San Antonio): Data Center Water Impact
Reference data for evaluating a data center proposal in Bexar County, TX (San Antonio). Every figure below is a stored value with its primary source attached. Facility-scale results are produced by the assessment tool.
Water supply
| Metric | Value | Source / basis |
|---|---|---|
| Water utility | San Antonio Water System (SAWS) | Utility of record |
| Supply source | Edwards Aquifer + diversified portfolio | Utility of record |
| Treatment capacity | 320 MGD | Water stress: WRI Aqueduct 4.0, HUC-8 12100301. Edwards Aquifer is sole-source — drought triggers cut municipal supply. |
| Water rate | $4.20 / 1,000 gal | San Antonio Water System (SAWS) published rate schedule |
| Watershed stress | Extremely High (4.2 / 5) | Water stress: WRI Aqueduct 4.0, HUC-8 12100301. Edwards Aquifer is sole-source — drought triggers cut municipal supply. |
Watershed consumptive use
Basin: San Antonio (HUC-8 12100301). Figures are consumptive use, not withdrawal, because evaporative data center loss is consumptive. USGS data year 2020.
| Category | Consumptive use (MGD) | Share of basin |
|---|---|---|
| Residential | 200 | 74.1% |
| Thermoelectric power | 25 | 9.3% |
| Industrial | 15 | 5.6% |
| Irrigation | 25 | 9.3% |
| Mining | 2 | 0.7% |
| Existing data centers | 3 | 1.1% |
| Total | 270 | 100.0% |
Total is the sum of the categories listed above. Shares are each category divided by that total. Source: USGS Water Use 2020, Bexar County. Edwards Aquifer Authority.
Grid generation water (Scope 2)
Generating the electricity a data center consumes evaporates water at the power plant. That volume is real, it is attributable, and it is excluded from most corporate "water positive" accounting. On a thermal grid it is frequently comparable to the facility's own cooling water.
| Metric | Value | Source / basis |
|---|---|---|
| Grid region | ERCOT | ERCOT |
| Electric utility | CPS Energy | Utility of record |
| Grid water intensity | 0.22 gal / kWh | Macknick et al. 2012 × ERCOT mix |
| Local peak demand | 4,500 MW | ERCOT |
| Modeled rate impact | 4% to 10% | See methodology |
Where this water is consumed: CPS Energy operates plants near San Antonio; some Scope 2 water occurs locally.
Run this county at your facility size. The assessment tool computes direct (Scope 1) and indirect (Scope 2) water for a specific load, cooling system, and mitigation stack, with the same citations attached.
Reducing the footprint here
A high stress reading is a design constraint, not a verdict. Closed-loop and dry or hybrid cooling, adiabatic assist, immersion, and reclaimed or non-potable sourcing each move the direct number, and siting against a cleaner grid mix moves the indirect number. The solutions catalog lists each option with its water reduction, its energy and cost tradeoff, and its source.
Regulatory and siting status
San Antonio. Edwards Aquifer is sole-source — significant constraints. Drought triggers cut municipal supply. Statewide: on 3 Aug 2026 the Governor directed the PUCT and ERCOT to audit every data center in the interconnection queue before any further project may advance, and ERCOT paused its Batch Zero study. The audit requires each project to disclose projected annual and peak water consumption, water sources, and cooling technology.
- Arid / water stressed
Sources: Water: SAWS. Edwards Aquifer Authority. Grid: ERCOT. Statewide audit: Office of the Governor, 3 Aug 2026.
Comparative siting scores for this county, alongside every other county tracked, are on the US Siting Matrix.
Related counties
| County | Water source | Watershed stress |
|---|---|---|
| Williamson County, TX (Austin metro) | Brazos River + Edwards Aquifer + reservoirs | High (4/5) |
| Denton County, TX (DFW) | Trinity River | High (3.5/5) |
How these numbers are derived
Assumptions, formulas, and the full source list are in the methodology. WaterMark is published by Standard Water Corp and is not affiliated with any data center developer, utility, or government agency.