Whole House Water Softeners in Denton

Denton has owned its water utility since 1905, and for its first half-century the water came entirely from deep artesian wells. The shift to lakes was gradual. In 1927, after Dallas built Lake Dallas, Denton declined a contract for storage in it. Three decades later the city helped pay for the new Garza-Little Elm dam, now Lewisville Lake, in exchange for access to its water, and in the 1980s it contracted for water from Lake Ray Roberts while the Corps of Engineers was still building it. Today Denton treats surface water from both lakes at its own plant beside each one, and it runs its own lake plants rather than buying from a wholesaler. The federal facility record shows how complete the change is: Denton’s system lists 17 wells marked plugged and no working well, two intakes, one on Lewisville Lake and one on Ray Roberts, and two surface water plants, the Lake Lewisville plant on Spencer Road and the Lake Ray Roberts plant, which the city’s own project page dates to 2002. A July 2024 Texas Water Development Board item put the two plants’ combined capacity at 48.9 million gallons a day against a demand of 42, and described a rating upgrade and a 20 million gallon a day expansion at Ray Roberts to carry the city to 2030; the city expects the re-rate alone to add 6 to 10 million gallons a day to that plant’s 20.

That is the kind of change that moves a town’s hardness, and it moved Denton’s in one direction. The deep sandstone aquifers under Denton County yield soft, sodium-rich water; the Mustang district’s wells in the same Trinity and Woodbine formations tested at under 6 ppm of hardness in its 2025 report, with sodium above 200 ppm. Reservoir water is the opposite: it carries the calcium and magnesium it collects from the land it drains, and the treated lake water that North Texas districts deliver is generally described as moderately hard; the North Texas Municipal Water District says so of its Lavon Lake water and tells homeowners to divide mg/L by 17.12 for grains per gallon. A Denton home of 1950, on artesian water, had little use for a softener. A Denton home today is on Lewisville and Ray Roberts water. Upper Trinity, which treats the same two lakes under contract with Dallas and Denton, says lakes are the region’s reliable supply because little water sits below ground to be pumped.

Denton’s own report does not print a hardness figure we could read, so we do not have a number for the city, only the direction: lake water, therefore harder than the Denton of the well years, and varying with the season and with which of the two plants is carrying the load. The federal record lists the city’s elevated tanks at Roselawn Circle, Riney Road, Interstate 35 at Loop 288 and Lively Road, and a 2 million gallon ground tank at McKenna Park, but no document we read says which plant fills which tank on a given day. The free water test puts a figure on it at your tap, in ppm and grains per gallon, and that reading, not a regional average, is what we size a softener to.

Sources: Handbook of Texas — Denton, TX · Handbook of Texas — Lewisville Lake · City of Denton — 2025 Water Quality Report · Mustang SUD 2025 Consumer Confidence Report, secondary constituents table · North Texas Municipal Water District — Water Quality · U.S. EPA Envirofacts SDWIS: water system facilities for TX0610002 · Texas Water Development Board, July 2024 Board item 15, City of Denton · City of Denton, Discuss Denton: Ray Roberts Water Treatment Plant Capacity Re-rate and Performance · Upper Trinity Regional Water District: Water Sources