Why the water is hard
Rain that soaks into the limestone of the Edwards Plateau dissolves calcium and magnesium on its way into the aquifer. That mineral-rich water is excellent to drink, but it leaves scale wherever it is heated or evaporates. SAWS blends several sources, so hardness varies by area; your annual water quality report and a simple test strip tell you what you actually have. Many Hill Country homes on private wells see even harder water.
What scale does
- Tank water heaters: sediment builds on the bottom, causing rumbling, lost capacity and earlier failure.
- Tankless heaters: scale coats the heat exchanger, triggering error codes and reduced flow. Annual descaling is part of owning one here.
- Fixtures: clogged aerators and showerheads, crusty valves and spotting on glass.
- Appliances: dishwashers, ice makers and washers lose efficiency.
Options, from cheapest up
Flush the tank heater yearly and clean aerators. Add isolation valves to a tankless unit so it can be descaled. A scale-control (template-assisted crystallization) system reduces scale without salt. A conventional softener removes hardness and protects everything downstream but must be sized to your flow and hardness, and it adds salt and backwash water.
Sizing a softener
A softener should be sized from hardness (grains per gallon) times daily use, with a valve that can pass your peak flow. Oversized units waste salt and money; undersized ones run out of capacity. Our Fixture Unit Calculator estimates peak flow, and our Water Heater Sizer covers the heater side.
Not sure which applies to your home? Start with the Plumbing Health Score or see the glossary for terms like scale, anode rod and sediment.