Can we use water while the system regenerates?

You may still have water during regeneration, but a single-tank softener will typically provide untreated hard water while it cleans itself. Avoid heavy water use—especially hot water—during this period so hard water does not refill the water heater.

Most systems regenerate overnight when household demand is low. Certain multi-tank configurations can provide treated water continuously, so the answer depends on your specific equipment.