Water Softeners and Water Treatment in Tarrant County, TX

Fort Worth's 2025 figures put total hardness at 108 to 150 ppm, or 6 to 9 grains per gallon. On the U.S. Geological Survey scale that runs from moderately hard to hard, and the city itself says its water is usually hard enough to coat the inside of metal pipes and fixtures. It disinfects with chloramines, averaging 3.3 ppm.

Keller and Southlake both buy their water from Fort Worth, so homes there get the same supply.

The Trinity River Authority's Tarrant County Water Supply Project pumps raw water from Lake Arlington to a plant on the Fort Worth and Euless line. It serves Bedford, Colleyville, Euless, Grapevine and North Richland Hills, about 250,000 people.

Grapevine uses that supply alongside water from Lake Grapevine. Its 2024 report lists 117 ppm of hardness for its own plant and 135 ppm for the authority's water, about 6.8 and 7.9 grains per gallon.

Mansfield buys its water from the regional district, drawn mainly from Cedar Creek and Richland Chambers reservoirs and Lake Benbrook. Its 2025 report lists hardness as calcium carbonate at 114 ppm, about 6.7 grains per gallon, and calls the water medium hard. The city also notes it has used chlorine dioxide since 2003 to reduce iron and manganese.

Arlington treats surface water too. In 2023 the city reported that algae in Lake Arlington can release compounds that give tap water a noticeable taste for some customers, and that it uses ozone treatment to manage taste and odor.

The Northern Trinity Groundwater Conservation District covers all of Tarrant County. Its management plan lists the northern Trinity and Woodbine aquifers among the county's groundwater resources, with the Trinity made up of the Paluxy and Twin Mountains formations separated by the Glen Rose.

The Texas Water Development Board describes Trinity groundwater as fresh but very hard where the aquifer reaches the surface, and says the upper zone of the Woodbine tends to be very high in iron.

The Texas Commission on Environmental Quality does not regulate private drinking water wells, so the owner is responsible for testing. The EPA recommends testing a private well every year for total coliform bacteria, nitrates, total dissolved solids and pH.