Heavy rain has turned the Hill Country's tap water into a temporary science experiment, and not the fun kind. Bulverde and dozens of communities that pull drinking water from Canyon Lake were placed under a boil‑water notice Thursday after flooding pushed sediment and debris into the reservoir, city and utility officials warned. Residents in the affected areas are being told to boil any water used for drinking, cooking and ice‑making until treatment levels return to normal. The order is described as a precaution to prevent illnesses that can happen when cloudy, high‑turbidity water interferes with disinfection.
Officials: Turbidity Triggered Notice
In a news release, The City of Bulverde said the Canyon Lake Shores Public Water System - PWS ID TX0460019 - "failed to meet the minimum treatment technique requirements" after combined filter effluent turbidity readings rose above 5.0 NTU. According to the city, that threshold breach prompted the Texas Commission on Environmental Quality to require the system to issue a boil‑water notice.
The city said the treatment plant saw a "significant influx of debris and sediment" following flooding along the Guadalupe River on July 15 and that the notice will stay in place until sediment levels drop and the water once again meets state standards.
Utility: Boil Or Use Bottled Water
Texas Water Company, which operates the Canyon Lake Shores system, posted the required public notice instructing customers to bring tap water to a vigorous rolling boil for two minutes before using it for drinking, cooking or ice‑making, or to use bottled water instead. On its service‑alerts page, the utility lists the specific subdivisions covered by the advisory and says treatment operations are being continuously monitored while corrective actions are carried out. Customers with questions are directed to the utility's customer‑service line.
Lake Surge After Flooding
Reservoir data from Water Data For Texas show Canyon Lake rising to about 66.5 percent full on July 16 after sitting near 61 percent a week earlier, a jump that local reports link to heavy rains and runoff. Coverage in MySA says flooding and runoff along the Guadalupe River likely carried in the sediment that drove turbidity levels up at the plant intake.
Past Problems And Fixes
The Canyon Lake Shores system has had storm‑related turbidity issues and disinfection‑byproduct concerns in previous years, and Texas Water Company's 2025 water‑quality report describes a series of corrective steps - including equipment upgrades and tighter monitoring and reporting - that are intended to cut down on repeat problems. Texas Water Company's 2025 report outlines the operational changes the utility says it has put in place following earlier exceedances.
What Residents Should Do
To guard against microbes that can survive in murky water, residents are advised to bring any water used for drinking, cooking or ice‑making to a vigorous rolling boil and keep it boiling for two minutes, then let it cool before use. The Texas Commission on Environmental Quality's boil‑water guidance notes that elevated turbidity can shield bacteria and other pathogens from disinfectants and lays out recommended boiling procedures and notification rules. Officials say commercially bottled water is an acceptable alternative for drinking and food preparation if residents prefer not to boil.
Questions And Updates
For questions, Texas Water Company lists customer service at (830) 312‑4600 and [email protected]. The utility and the City of Bulverde are posting updates on their service‑alerts and news‑flash pages. For more on state requirements and what a boil‑water notice means, residents can look to guidance from the Texas Commission on Environmental Quality and the utility's public notice.
