During regeneration, water flow is reserved to backwash which cleans the resin bed. Brine is pulled in and then rinsed out to regenerate the resin, preparing it to soften more water. The brine tank is then refilled with fresh water for future cycles. The control valve body can be made of brass or plastic to fit any plumbing system. Regeneration cycles can be preset with a time control or can be based on water usage with a meter.
Controls are available in digital electronics or mechanical designs.
The resin attracts and collects minerals from hard water. Once the resin is saturated with hardness minerals it must be cleaned and regenerated. Once regenerated, the resin is ready to clean more water. Resin tanks can be exposed or covered with a jacket or insulated jacket. Historically, resin tank construction was metal.