San Juan Water Hardness & Quality Report (2026)

The City of San Juan Utilities Department serves San Juan in Hidalgo County, Texas, part of the Lower Rio Grande Valley. Drinking water is supplied primarily from groundwater in the Gulf Coast Aquifer, specifically the Evangeline formation. Treatment occurs at local wellhead facilities and distribution plants managed by the department, ensuring compliance with state and federal standards detailed in annual Consumer Confidence Reports. The utility can be reached at 956-223-2311. Treatment involves chlorination, fluoridation, and basic filtration at wells, with routine testing covering disinfection byproducts, nitrates, and bacteria.

San Juan's water originates from the Gulf Coast Aquifer system, a vast groundwater basin spanning South Texas without a traditional surface watershed. The primary formation is the Evangeline Aquifer — Miocene to Pliocene sands and clays — with overlying Lagunilla Formation contributions and underlying input from the Yegua Formation. This geology, dominated by calcareous sands and prolonged contact with limestone and dolomite within the aquifer matrix over Tertiary and Quaternary periods, enriches groundwater with dissolved calcium and magnesium through natural leaching, producing a characteristically hard supply.

Hard water in San Juan causes scale buildup in pipes, water heaters, dishwashers, washing machines, and coffee makers, where mineral deposits clog elements and valves, reducing efficiency and lifespan. Regular vinegar descaling, flushing systems, and installing drain screens are advised maintenance strategies. A water softener is recommended to protect plumbing, improve soap efficiency, and extend appliance life. The 2023 Consumer Confidence Report confirms compliance with all federal drinking water standards; pH is typically neutral to slightly alkaline due to natural buffering, and no notable violations have been reported.