Hardness is dissolved calcium and magnesium, measured in grains per gallon. Water from wells and groundwater sources in the Central Valley often runs hard. The minerals stay dissolved until the water is heated or evaporates, then they leave scale: in the bottom of the water heater, inside tankless heat exchangers, on faucet aerators and shower glass.
A water softener removes hardness minerals through ion exchange, which protects your water heater and fixtures and makes soap work better. It does not filter the water for taste or contaminants. Filtration is the other half: a whole-house carbon filter reduces chlorine taste and odor at every tap, and an under-sink reverse osmosis system gives you filtered drinking water at the kitchen sink.
Many homes benefit from one and not the other. A softener uses salt and needs a drain and an outlet nearby. We test hardness and look at your plumbing before recommending anything, and we are glad to tell you when you do not need a system at all.