How Hard Water Affects Swimming Pools

"Hard water" refers to water that contains high concentrations of dissolved minerals, primarily calcium and magnesium. In the Las Vegas Valley, our municipal water supply is drawn from the Colorado River via Lake Mead, making it some of the hardest water in the country. This presents unique challenges for pool maintenance.

Cloudy Water and Poor Clarity

When water becomes oversaturated with calcium, the minerals precipitate out of solution. Before they attach to surfaces as scale, they float freely in the water. This suspended calcium carbonate reflects light, causing the pool water to look cloudy, milky, or dull, even when chlorine levels are perfect.

Equipment Degradation

Hard water is particularly destructive to pool equipment. As water passes through a pool heater, the heat causes calcium to drop out of solution rapidly, coating the internal copper heat exchanger. This scale acts as an insulator, forcing the heater to work harder, wasting gas, and eventually causing the core to melt down. Similarly, salt chlorinator cells become quickly encrusted with scale, stopping chlorine production entirely.

Surface Scaling and Rough Plaster

The most visible effect of hard water is the white, crusty scale that forms on the waterline tile. Less visible, but equally damaging, is the scale that forms on the plaster itself. Over time, calcium nodules can grow on the pool floor and walls, creating a surface that feels like rough sandpaper, which can scrape swimmers' feet.

Professional Mitigation

While we cannot change the source water, we can manage its effects. Strict adherence to the Langelier Saturation Index (LSI) by balancing pH and alkalinity is crucial. We also utilize professional-grade sequestering agents to keep calcium suspended in solution, protecting your surfaces and equipment from the harsh realities of desert water.