Softener or conditioner: treating San Jose's hard water

How hard the water is

San Jose Water Company counts anything above 7 grains per gallon as hard. Its data for groundwater serving most of the valley floor runs roughly 11 to 26, and imported surface water reaching parts of the system is softer. The white film on showerheads and glass is the residue of that hardness, left when water heats or evaporates.

Because the blend varies by street and season, the first step is a hardness test at your own tap.

How a salt-based softener works

A softener passes water through resin beads that swap calcium and magnesium for sodium or potassium. The water leaving it is soft: no scale in the heater, no film on glass, and soap lathers easily. Periodically the resin is regenerated with brine from a salt tank, and that rinse water goes to a drain.

It needs a spot near the main line, a drain for regeneration with an air gap, an outlet for the control head, and someone to top up the salt. Many owners keep a hard-water hose bib for the garden.

How a salt-free conditioner works

Most salt-free conditioners use template-assisted crystallization: the media turns dissolved hardness into tiny crystals that stay suspended in the water instead of sticking to hot surfaces. Scale in heaters and on fixtures drops, but the minerals are still there, so the water does not feel softened and glass still spots.

It needs no drain, no salt and no electricity, which makes placement easy.

Which one suits which house

If you own a tankless water heater, have a tank that keeps failing early, or simply want the full effect of soft water, a salt-based softener is usually the right choice. If there is no practical drain near the main, someone in the house is watching sodium intake, or the main goal is modest scale reduction, a conditioner is a reasonable alternative.

Either way, size matters. A softener is sized from your hardness and household water use, so it regenerates every few days rather than every night.

Where a filter fits

Neither a softener nor a conditioner removes the disinfectant. San Jose uses chloramine, which ordinary activated carbon handles poorly; catalytic carbon is needed. If you want better-tasting water throughout the house, a whole-house catalytic carbon filter can sit alongside the softener. For drinking water only, a reverse osmosis system at the kitchen sink is the usual choice.