Whole House Water Softeners in Highland Park

Highland Park's water takes a long route for a short distance. The Dallas County Park Cities Municipal Utility District asks the Corps of Engineers to release water from the Grapevine Lake dam into Denton Creek; it flows into the Elm Fork of the Trinity, is captured at Ski Lake near Highway 114 and Northwest Highway, and travels by pipeline to the district's plant at 1811 Regal Row. There it is dosed with lime slurry and ferric sulfate, settled in clarifiers, run through granular activated carbon filters, disinfected with chlorine and ammonia to form chloramine, and finally pushed through membranes that stop particles 0.4 microns and larger, a system that came online in 2013 after $33 million in bonds sold in 2010. The finished water rests in a 10 million gallon underground clear well before it leaves for the two Park Cities. The town's 2025 report records 6.94 percent of the water bought from the district as lost in the town's own mains, and notes two interconnections with Dallas Water Utilities kept for emergencies and maintenance.

The district says it measures hardness to check its lime softening process, and the town's figures show the process working. Highland Park's 2025 report prints tap water hardness at an average of 42 mg/L in a range of 28 to 93, naturally occurring calcium and magnesium. That is about 2.5 grains per gallon on average, about 1.6 at the low end and about 5.4 at the top: soft on the USGS scale through most of the year, moderately hard at the highest reading. The rest of the table fits that picture. Total alkalinity and bicarbonate both read 40.5 mg/L, pH averaged 8.7 in a range of 8.34 to 9.06, magnesium was 5.15 mg/L, sodium 33.4, sulfate 99.1 and total dissolved solids 248. A low alkalinity and a high pH are what lime treatment leaves behind. The same Grapevine Lake water, treated at Dallas's Elm Fork plant without the district's softening step, is part of the blend Dallas puts at 120 to 155 mg/L.

At a Highland Park tap that means a softener has little work to do. Forty-two mg/L is water that rinses clean and leaves little scale, and even the 93 mg/L high reading is under the hard line. The spread between 28 and 93 is within one year at the town's own taps; the report does not say whether the emergency Dallas connections were in use on any sampling day, and the town does not publish a figure by street. If a softener is wanted here, it should be sized to the top of the town's range, about 5.4 grains per gallon, and the free water test will tell you whether your tap is at the soft end of the range or the moderately hard one.

Sources: Town of Highland Park 2025 Drinking Water Quality Report · Dallas County Park Cities Municipal Utility District, About · City of Dallas memorandum, December 1, 2023