Water Softeners and Water Treatment in Denton County, TX

Water from Lewisville and Ray Roberts lakes is treated at the district's Thomas E. Taylor plant in Lewisville; a second plant, Tom Harpool, sits in Providence Village. More than 103 miles of pipeline carry the water to over 20 member and customer cities, towns and utilities, and the district adds a small amount of chloramine, chlorine plus ammonia, as its disinfectant.

Highland Village mixes two sources. Its report says the city's water comes from purchased surface water and self-supplied groundwater, from the Trinity Aquifer and Lewisville Lake, and that it buys the surface water from the district.

Its hardness column, sampled in 2022, reads 6.16 to 65.5 ppm, soft to the low end of moderately hard on the U.S. Geological Survey scale. Dissolved solids, sampled in 2023, run 400 to 798 ppm, against an EPA secondary guideline of 500 tied to deposits, staining and salty taste. Chloramine averaged 2.6 ppm in 2024.

The newest City of Denton report we could read, from 2019, says Denton uses surface water from Lake Lewisville and Lake Ray Roberts and disinfects with chloramines. That report does not list hardness.

Denton County shares a groundwater district with Collin and Cooke counties: the North Texas Groundwater Conservation District, whose 2012 plan names the Northern Trinity and Woodbine aquifers. The Texas Water Development Board reports that some of the state's largest Trinity water level declines, from 350 to more than 1,000 feet, occurred in counties along the IH-35 corridor from McLennan County to Grayson County, mainly from municipal pumping. That page does not say which counties.

TCEQ does not regulate private drinking water wells, so maintenance and testing are the owner's job. The EPA's advice is a yearly test for coliform bacteria, nitrates, dissolved solids and pH, plus an immediate one whenever odor, color or taste changes.