Cibolo Water Hardness & Quality Report (2026)

The City of Cibolo Public Works Department manages the municipal water utility serving Cibolo in Guadalupe County, Texas, with a service area covering the city and surrounding developments. Water is sourced primarily from groundwater wells tapping the Edwards Aquifer and Trinity Aquifer. Treatment occurs at the city's Water Treatment Plant, which processes raw groundwater through filtration, disinfection, and chemical adjustment before distribution to approximately 30,000 residents. The Cibolo Creek Watershed, spanning about 90 stream miles before joining the San Antonio River, influences surface hydrology, but the municipal supply relies entirely on groundwater from these underlying aquifers.

The Edwards Aquifer and Trinity Aquifer underlie the region within the Balcones Fault Zone, consisting of Cretaceous-era limestone and dolomite formations. The Edwards Group (Comanchean Series) and Trinity Group sands and limestones feature karst topography with solution channels that enhance mineral leaching. The karstic nature of the Edwards limestone allows rapid infiltration of rainwater, dissolving calcium carbonate-rich rock and imparting a hard character through elevated concentrations of calcium and magnesium ions during subsurface flow through fractured carbonate bedrock.

Hard water from the Edwards Aquifer causes moderate scale buildup in water heaters, dishwashers, and coffee makers, reducing efficiency and increasing energy costs. Laundry may feel stiff and soap lathering is less effective, requiring more detergent. Annual descaling of fixtures and heaters is advised. A water softener is recommended for households with noticeable spotting on dishes or a film on skin after bathing. Treatment involves chlorination for disinfection and corrosion control; compliance with TCEQ standards is maintained — consult the annual CCR for the latest monitoring details.