Water Resources

Quick links

• West Texas Water Partnership
• Lake Nasworthy
• Hickory Aquifer
• Concho River Water Project

General water information

• Population: 101,004.
• Water connections: 35,733.
• Water demand by customer category: 
    - Residential — 73% 
    - Commercial — 12% 
    - Industrial — 4% 
    - Institutional — 11%

Water demand

Annual daily average: 12.5 million gallons.
Summer peak: 24 million gallons per day.
Winter daily average: 10 million gallons per day.
Average annual usage: 13,441 acre-feet. An acre-foot equals 325,851 gallons.

Water supplies 

Current water supplies are surface water (reservoirs and lakes) and the required minimum daily groundwater production from the Hickory Aquifer, which is approximately 1.5 million gallons per day. As of February 1, San Angelo had 41 months of water supply. That is a worst-case scenario that assumes no rainfall or runoff into reservoirs over that time span.

Primary sources

O.H. Ivie Reservoir 
• Owned and operated by the Colorado River Municipal Water District.
• Purpose: Water supply.
• Supplies: Odessa, Big Spring, Snyder, Midland, Abilene, San Angelo, Ballinger and Millersview-Doole. 
• Storage capacity: 554,339 acre-feet. An acre-foot equals 325,851 gallons. 
• Capacity filled: 39% as of March 1, 2023.
 
Twin Buttes Reservoir

• Owned by the U.S. Bureau of Reclamation. Managed under contract by the City of San Angelo.     
• Purpose: Water supply, irrigation and flood control.
• Supplies: City of San Angelo, Tom Green County and Water Control Improvement District No. 1.
• Storage capacity: 186,244 acre-feet. An acre-foot equals 325,851 gallons. 
• Capacity filled: 33% as of March 1, 2023.

Lake Nasworthy 
• Owned and operated by the City of San Angelo.
• Purpose: Water supply.
• Supplies: City of San Angelo.
• Storage capacity: 12,500 acre-feet. An acre-foot equals 325,851 gallons. 
• Capacity filled: 87% as of March 1, 2023.

O.C. Fisher Reservoir
• Owned and operated by the Upper Colorado River Authority.
• Purpose: Water supply and flood control.
• Supplies: City of San Angelo and UCRA.
• Storage capacity: 119,000 acre-feet. An acre-foot equals 325,851 gallons. 
• Capacity filled: 3% as of March 1, 2023.
 
Lake Spence  
• Owned and operated by the Colorado River Municipal Water District.
• Purpose: Water supply.
• Supplies: Odessa, Big Spring, Snyder, Midland and San Angelo.
• Storage Capacity: 488,000 acre-feet. An acre-foot equals 325,851 gallons. 
• Capacity filled: 18% as of March 1, 2023.

Newer and future water supplies 

• Hickory Aquifer expansion
• Concho River Water Project
• West Texas Water Partnership - Fort Stockton Holdings

Drought levels

Stages are based on available supply from all surface water sources:

• Standard conservation: more than two years supply. 
• Drought Level 1: less than two years supply.
• Drought Level 2: 18 months or less.
• Drought Level 3: 12 months or less.

With approximately 41 months of supply as of Feb. 1, 2023, the City is in standard conservation, which restricts outside watering to twice every seven days at no more than 1 inch per week. Watering is prohibited between noon and 6 p.m. Runoff of more than 150 feet down any street, gutter, alley or ditch is also prohibited.

Report watering violations online or by calling 325-657-4409. For more information, go to cosatx.us/water. Do your part; be water smart!