San Angelo, Texas, draws its drinking water primarily from reservoirs and lakes, a system that requires rigorous treatment to meet regulatory standards. The quality of municipal water is constantly monitored but can be affected by environmental factors like drought and facility maintenance. Understanding the source, treatment, and specific contaminants helps residents assess the safety of their tap water.
Current Safety Status and Advisories
The City of San Angelo’s water is generally safe to drink, meeting most federal and state health standards established by the Texas Commission on Environmental Quality (TCEQ) and the Environmental Protection Agency (EPA). The city has experienced occasional violations, particularly concerning disinfection byproducts. For example, in late 2024, the city exceeded the Maximum Contaminant Level (MCL) for Total Trihalomethanes (TTHMs) during two quarterly periods, though no immediate health risk was identified.
Regulatory exceedances do not typically pose an acute health threat, but they require public notification and corrective action. Residents should refer to the City of San Angelo Utilities Department website for real-time information, including active boil water notices or public service announcements. The city publishes an annual Consumer Confidence Report (CCR) that contains the official water quality data from the previous calendar year.
Water Sources and Treatment Infrastructure
San Angelo uses a blend of surface water and groundwater sources. The primary surface water sources include O.H. Ivie Reservoir, Lake Nasworthy, Twin Buttes Reservoir, O.C. Fisher Reservoir, and Lake Spence. The city supplements this supply with groundwater drawn from the Hickory Aquifer, which is piped from McCulloch County.
Reliance on surface water introduces variability, as lake water contains more dissolved organic matter than groundwater. This organic load fluctuates based on weather conditions and drought cycles. The treatment process involves coagulation, sedimentation, filtration, and disinfection to remove impurities. The city employs chloramine disinfection to ensure the water remains safe throughout the extensive 677-mile distribution system.
Specific Contaminants of Concern
The most frequent regulatory challenge involves disinfection byproducts, specifically Total Trihalomethanes (TTHMs) and Haloacetic Acids (HAA5s). These compounds form when disinfectant reacts with naturally occurring organic materials in the source water. Since San Angelo relies heavily on surface water, which is rich in these organic precursors, managing these byproducts is an ongoing process.
The EPA sets the Maximum Contaminant Level (MCL) for TTHMs at 0.080 milligrams per liter (mg/L) based on a running annual average. When the city’s groundwater facility was temporarily offline, the increased reliance on surface water led to TTHM levels that briefly exceeded this limit. Long-term exposure to TTHMs above the MCL is associated with increased risks affecting the liver, kidneys, central nervous system, and potential cancer risks.
The city’s primary strategy for mitigating TTHM formation is blending surface water with treated groundwater from the Hickory Aquifer, which contains less organic material. The city also monitors for heavy metals like lead and copper. These metals typically enter the water from service lines and household plumbing, especially in older homes. A recent administrative violation involved a delay in providing lead test results to customers, underscoring the importance of infrastructure monitoring.
Practical Steps for Residents
Residents can monitor their water quality by reviewing the annual Consumer Confidence Report (CCR), which details the previous year’s testing results for all regulated contaminants. This report is published by the Water Utilities Department and is the most comprehensive source for compliance data. Understanding the contaminants detected allows residents to choose appropriate home filtration methods.
To address taste, odor, or specific contaminants like TTHMs, a home filtration system is an option. Simple pitcher filters or faucet-mounted devices often use activated carbon, which is effective at removing disinfection byproducts and improving flavor. For more comprehensive treatment, residents may consider a whole-house activated carbon filter or a reverse osmosis system.
In the rare event of a boil water notice, the procedure is to bring all water used for consumption to a rolling boil for at least one full minute and then allow it to cool. This measure is designed to kill potential microbial contaminants that may have entered the system. Residents with health concerns related to any water quality report should consult their physician.