Seventeen Grains Per Gallon
What Buda's Fill Water Does to a Backyard Pool
The City of Buda blends Edwards Aquifer wells with Canyon Lake surface water (GBRA) and Alliance Regional Water Authority supply. The mix tests around 17 grains per gallon, roughly 290 ppm hardness, which lands a freshly filled pool near the middle of the 200 to 400 ppm calcium target. Evaporation, well over 50 inches a year off a pool surface here, leaves every grain of mineral behind, so a pool that has never been partially drained can pass 400 ppm within a couple of summers. Ruby Ranch and the west-side acreage fill from private wells, and those are hard as well.
So we don't fight the water in Buda; we plan around it. Every visit includes a calcium hardness reading, and we calculate the saturation index rather than eyeballing the tile line. pH gets held at 7.4 to 7.6 with alkalinity in the lower half of 80 to 120 ppm, because high pH on top of high calcium is the recipe for scale. We shock with products that don't add calcium wherever we can, since cal-hypo puts more mineral into water that already has plenty. When calcium approaches 500 ppm, we book a partial drain and refill for the cooler months.
The pools are mostly 2005 to 2024 production builds on small and mid-size lots: cartridge filters, variable-speed pumps, and salt systems on many of the newer ones. In the newer subdivisions the yards are full sun; unstabilized chlorine is gone within hours under July sun, and demand roughly doubles versus spring. Garlic Creek and the older streets around Main Street run the other way: mature trees dropping live oak catkins in March and April and leaves in the fall. Add construction dust from ongoing building, young families who use their pools hard, and Blackland clay east of I-35 that heaves and shrinks with every drought.