Water softening and filtration for San Jose homes on San Jose Water, Great Oaks Water or San Jose Municipal Water, starting with a free water assessment.
Most of San Jose is served by San Jose Water, which blends Santa Cruz Mountains surface water, local groundwater and treated water bought from Valley Water. Parts of south and central San Jose are on Great Oaks Water's own wells, and the north, Alviso, Evergreen, Edenvale and Coyote Valley are on San Jose Municipal Water.
San Jose Water's 2025 report puts the hardness of its groundwater at an average of 288 ppm, against 99 ppm for the Valley Water supply it blends in. Great Oaks Water, which pumps only its own wells, reports an average of 241 ppm in 2025 and disinfects with free chlorine rather than chloramine. That mineral load is the white crust on faucets and the scale that builds inside a water heater.
The way we work does not change from house to house. We look up the public data on your water, tell you what your home actually needs, and put it in for one all-in price.
In San Jose we start by confirming which of the three utilities feeds your street, then fit the system where your main line enters the house, often in the garage.