Two homes in the Houston area can have very different tap water, even a few miles apart. It comes down to who supplies the water and where it comes from.
City water is a blend
The City of Houston’s 2025 water report shows its main system is 90.3% surface water from Lake Houston, Lake Conroe and Lake Livingston, and 9.7% groundwater from deep wells. Even within that one system, hardness ranged from 43.5 to 229 ppm, with an average of 135.5 ppm.
Many suburbs are served by utility districts
Much of the area outside city limits, including Cy-Fair, is served by municipal utility districts that have historically relied on groundwater. To reduce land subsidence and meet Harris-Galveston Subsidence District rules, the North Harris County and West Harris County regional water authorities have been shifting toward surface water. Community Impact reported in 2025 that surface water made up about 32% to 34% of the north authority’s usage and 35.64% of the west authority’s.
That means the mix coming out of your tap may be changing, and it may not match what your neighbor in another district gets.
What that means for your home
- Your hardness can be very different from a city average
- Taste and odor can change as your supplier’s mix changes
- Homes on private wells need their own testing
The only way to know what is in your water is to test it at your tap. From there, a water softener, filtration or reverse osmosis can be matched to your actual water.
Get your water tested for free
Culligan of Houston serves Houston, Cypress, Katy, The Woodlands, Sugar Land and the surrounding area. Our local team can test your water at your home at no cost. Schedule your free water consultation.
