Microsoft County Road 381 Campus (SAT93/SAT94)
Buildings
2
Building area
490,000 sq ft
Cooling
Evaporative cooling (assumed; Microsoft standard)
Investment
$0.7B
Developer
Microsoft Corporation
Microsoft filed plans in May 2025 for two data centers (SAT93 and SAT94) along County Road 381 in unincorporated Medina County, each spanning 245,000 sq ft and costing $350 million. Construction began August 2025 with completion targeted Winter 2028. Microsoft controls roughly 1,451 acres in Medina County. A Microsoft blog confirms construction updates for the CR 381 campus.
Water Impact
Daily water use (estimated range)
Unknown
Water returned per day
None reported
Per MW capacity not disclosed; water provider unconfirmed — outside SAWS service area, likely on-site well or Medina County water authority, based on Medina County location outside SAWS service area
vs. 5M gal/day (typical 400 MW facility)
- Water intake
- Unknown
- Lost to evaporation
- 100%
- Returned to system
- 0% (None reported)
Direct water figures are estimates from permit applications and developer disclosures. Indirect (power generation) figures are calculated estimates. Actual water use depends on technology choices, operating capacity, and weather conditions.
Location
Address: County Road 381, Castroville, Medina County, TX
Distance to aquifer edge: 0 miles
Infrastructure
- Power provider
- AEP / ERCOT
This project needs your attention.
Permitted — the decision is made, but conditions still matter
The primary decision cannot be undone, but the conditions attached to the approval can still be negotiated or enforced. Officials can be held accountable for permit violations. Community pressure matters for shaping how the project is operated and what monitoring is required.
Timeline
November 1, 2025
Texas Monthly reports on Microsoft's water negotiations in Medina County
Texas Monthly published a feature in November 2025 documenting how Yancey Water Supply's Scooter Mangold told Microsoft engineers "they'd lost their minds" over initial water requests, ultimately proposing a switch from evaporative to air cooling that reduced the facility's projected water needs by roughly 85 percent — to approximately 150,000 gallons per day.
Source →(opens in new tab)October 3, 2025
KSAT investigates billion-dollar data centers in water-stressed Medina County
KSAT12 published an in-depth investigation on October 3, 2025 examining the cumulative water and land impacts of multiple data center projects in Medina County, including Microsoft's County Road 381 campus. The piece noted that Medina County was experiencing exceptional drought and quoted local officials aware of at least eight data centers in various stages of development.
Source →(opens in new tab)May 13, 2025
Construction begins on SAT93 at County Road 381
Microsoft broke ground on the SAT93 data center at County Road 381, Medina County on May 13, 2025, per the TDLR project record. The 245,000 sq ft, $350 million single-story facility is the first of at least two buildings Microsoft filed to build along this corridor, targeting completion by June 2027.
Source →(opens in new tab)February 18, 2025
TDLR TABS filing for SAT93 data center (TABS2025012185)
Microsoft registered the SAT93 data center project with the Texas Department of Licensing and Regulation on February 18, 2025. The single-story, 245,000 sq ft building at County Road 381 in Medina County carries an estimated construction cost of $350 million, with construction scheduled to start May 13, 2025 and complete by June 15, 2027.
Source →(opens in new tab)
Documents
Sources
- 1. County Road 381 datacenter construction update — Microsoft Local, 2025-08-01. Link →(opens in new tab)
- 2. The impact of billion-dollar data centers in water-stressed Medina County — KSAT, 2025-10-03. Link →(opens in new tab)
- 3. How One Texas County Struck a Deal With Its Data Centers — Texas Monthly, 2025-11-01. Link →(opens in new tab)
Community Notes
Both buildings are on the Edwards Aquifer recharge zone in Medina County, which is experiencing exceptional drought. Texas Monthly documented Medina County residents' concerns about data center water use in late 2025. KSAT reported on "billion-dollar data centers in water-stressed Medina County" in October 2025. Medina County water supply is strained by data center growth.