Why San Antonio Water is So Hard

If you live in San Antonio, you're likely very familiar with hard water. The chalky white residue on your faucets, the spots on your glassware, and the dry skin after a shower are all telltale signs. But why is the water here so notoriously hard?

The Edwards Aquifer

The primary reason for San Antonio's hard water lies in its source: the Edwards Aquifer. This massive underground reservoir provides the majority of the city's drinking water. The aquifer is an artesian system composed primarily of highly porous limestone.

The Journey of the Water

As rainwater falls and seeps into the ground to recharge the aquifer, it passes through layers of this limestone rock. Limestone is made up of calcium carbonate and magnesium carbonate. The slightly acidic rainwater dissolves these minerals, carrying them into the aquifer and, eventually, into our municipal water supply.

Measuring the Hardness

Water hardness is typically measured in grains per gallon (GPG) or parts per million (PPM). Anything over 7 GPG is considered hard. San Antonio's water often registers between 15 and 20 GPG, placing it firmly in the "extremely hard" category.

What You Can Do

Because the source of our water is inherently rich in these minerals, the municipal treatment plants don't remove them (as they aren't a health hazard). To protect your home and enjoy soft water, installing a whole-home water softening system is the most effective solution for San Antonio residents.