Arlington Water Hardness & Quality Report (2026)

Arlington's water is supplied by the City of Arlington Water Utilities Division, drawing from a combination of local reservoir sources and regional water authority supply. Lake Arlington — a reservoir on Village Creek, an East Fork Trinity River tributary within the city — and Lake Benbrook on the Clear Fork Trinity River southwest of Fort Worth provide direct surface water supply. Arlington also participates in the Tarrant Regional Water District (TRWD) system, receiving blended supply from Eagle Mountain Lake, Lake Bridgeport, and other TRWD reservoirs in the upper West Fork Trinity watershed. The Arlington Water Treatment Plant processes the blended supply from these multiple Trinity basin sources.

Arlington's very hard water at 287 mg/L reflects the carbonate geology of the upper Trinity River watershed that all its sources share. The Trinity tributaries drain through the Fort Worth Prairie and West Cross Timbers — a rolling terrain underlain by Cretaceous Paluxy Formation sandstone and Comanche Peak Limestone — and the Upper Cretaceous Woodbine Formation sandstone and Eagle Ford Group marls and chalks. These Cretaceous marine formations were deposited 95–112 million years ago in the warm Western Interior Seaway and contain high calcium carbonate content. Arlington draws from the same watershed geology as Fort Worth and Dallas, explaining the similarly high hardness values across the DFW metroplex.

Arlington households face the same hard-water challenges common across DFW — thick white scale on all water-exposed surfaces forming rapidly, poor soap and shampoo lather, dishwasher spotting, and reduced appliance lifespan without maintenance. A whole-house water softener is the standard practical upgrade for Arlington homes, and the Tarrant Regional Water District provides educational resources on hard-water appliance protection. Descaling water heaters annually and maintaining showerhead vinegar soaks monthly are minimum routine measures to prevent premature fixture and appliance failures in this very hard water environment.