Whole House Water Softeners in Union Valley

Union Valley's utility, Cash Special Utility District, runs two different waters through one organization. Its 2025 water quality report explains that the district's own plant takes raw water from Lake Tawakoni and treats it by sedimentation, filtration and disinfection, and that this water goes to the Cash service area south of Interstate 30, Lone Oak and Cumby. The district's plant page puts that facility at 6001 County Road 3515 near Quinlan with a capacity of 4.2 million gallons a day. The second supply is finished water the district purchases from the North Texas Municipal Water District, treated at the Wylie plant from Lavon Lake, and the report assigns it to southeast Caddo Mills, Quinlan and the Union Valley side of the system. A Union Valley tap, then, is on the purchased water, not on the Tawakoni plant. Federal facility records trace the district's hardware on the Union Valley side: a pump station at 9428 FM 35 with pumps rated 960 gallons a minute and ground tanks of 0.200 and 0.04 million gallons, and an elevated tank of 0.200 million gallons at 4331 County Road 2522 in Union Valley, within a system of 9,997 connections that also keeps an emergency connection to Greenville.

That distinction decides the number. Page 6 of the Cash SUD report prints its secondary constituents in two columns, one for water from its own plant and one for the district water. The Cash SUD column shows total hardness of 66 ppm as calcium carbonate, with calcium at 22.5 ppm, magnesium 2.39, sodium 27.2, total alkalinity 49 to 79 and total dissolved solids of 170 ppm. The NTMWD column, the one that applies to Union Valley, shows total hardness of 200 ppm at the highest, in a range of 96.0 to 200, with sodium 41.9 to 88.0 ppm, alkalinity 43.6 to 138 as calcium carbonate, calcium 31.2 to 61.3 ppm with magnesium 6.27 to 9.44, on 182 to 455 ppm of dissolved solids. The site's figure of 200 ppm for Union Valley is that district number. In grains, 66 ppm is about 3.9, while the purchased water spans roughly 5.6 grains up to 11.7, which on the USGS scale runs from moderately hard to very hard; the Tawakoni plant water, by the same scale, sits in the moderately hard band.

For a homeowner in Union Valley the practical point is that the softer Tawakoni water a few miles away is not the water in your pipes. What arrives is Lavon Lake water that the regional district describes as moderately hard because of the minerals that lake carries, and in 2025 its hardness doubled between its lowest and highest readings as the blend and the season changed. Every house on the purchased-water side sees the same swings as its neighbors, since there are no wells or local blending to vary it street by street. The district's report adds local texture: it sent out 938,019,000 gallons in 2025, its chlorine residual ran from .50 to 4.00 ppm in both of its waters, and only the purchased-water column shows chlorine dioxide, 0.82 ppm, and chlorite, 0.95 ppm, a disinfection signature that marks which supply a tap is on; lead tested at 0.0114 ppm at the 90th percentile in 2024. If the district ever shifts a service area between its two supplies, the hardness at that tap would change with it, which is one more reason to test rather than assume. A softener here should be sized to the 200 ppm top of the range, about 12 grains, and the free water test gives the day's actual reading for your address.

Sources: Cash Special Utility District 2025 Annual Drinking Water Quality Report · Cash SUD, Treatment Plant page · EPA Envirofacts SDWIS, water system record record for TX1160018 Cash SUD · EPA Envirofacts SDWIS, water system facility records records for TX1160018 Cash SUD · North Texas Municipal Water District, Water Quality page