Cleaning a water softener means three separate jobs that people tend to lump together: emptying and washing out the brine tank, sanitizing the resin bed, and clearing the small passages in the control valve that actually draw the brine. Doing the first without the others is why a softener can look spotless and still fail to soften. Work in order, with the unit bypassed and unplugged, and give the tank time to dry before it goes back into service.
Emptying and washing the brine tank
Put the unit into bypass so the house keeps water, unplug the control valve, and disconnect the brine line at the tank. Scoop out the remaining salt and check for a salt bridge, which is a hard crust spanning the tank with an empty cavity underneath, and for salt mush, a sludge of fine crystals at the bottom that will not dissolve properly. Break a bridge carefully with a broom handle rather than hammering at it, since cracking the tank turns a chore into a replacement. Lift out the brine well and the grid plate if one is fitted, tip the residue out, and wash the tank with warm soapy water and a soft brush. Rinse thoroughly, because leftover detergent will foam through the resin bed on the next regeneration.
Sanitizing without damaging the resin
Sanitizing is worth doing after a flood, after any period out of service, when the water has an off smell, or on the schedule in the manual. Most manufacturers specify a measured dose of plain unscented household bleach poured into the brine well, followed by a manual regeneration to draw it through the resin bed and rinse it out. Read the manual first, because some resins and some coated media must never see chlorine, and using bleach on those destroys the bed. Do not drink the water until the regeneration has finished and the taps have been flushed. If the unit sits on a well that has had a bacteria hit, sanitize the well itself first, or the softener will simply be reinoculated.
Cleaning fouled resin, especially on well water
Resin does not wear out so much as get coated. Iron is the usual culprit, and Penn State Extension notes that a softener only removes dissolved iron where pH is above 6.7, hardness is between 3 and 20 grains per gallon and dissolved iron is under 5 mg/L, while oxidized iron fouls the resin. That is why a well household often needs a resin cleaner, a mild acid or reducing agent dosed into the brine well before a manual regeneration, on a routine schedule rather than as a rescue. Iron-fouled resin looks rust-stained when a sample is drawn, and if regular cleaning no longer restores capacity the bed itself needs replacing rather than cleaning again.
The parts everyone forgets
If the softener is not drawing brine, the problem is usually in a passage narrower than a pencil lead. The injector, also called the venturi, and its screen sit under a cap on the control valve, and salt fines or sediment block them routinely. Depressurize, remove the cap, lift out the injector and screen, and rinse them in clean water with a soft brush, never a wire. Check the brine line for kinks and make sure the ferrule and nut seal properly, since an air leak there stops brine draw entirely. Look at the safety float in the brine well and free it if it is stuck. Our water softener installation guide covers where each of those parts sits on a typical install.
Questions people ask about how do you clean a water softener
How often should a water softener be cleaned?
Wash the brine tank when you can see sludge or when you change salt type, sanitize on the manufacturer's schedule, and clean the resin routinely if the supply carries iron.
Can I use bleach in my water softener?
Only if the manufacturer's manual says so and only plain unscented bleach at the stated dose. Some resins and coated media are ruined by chlorine, so check before pouring anything in.
What is a salt bridge and how do I clear it?
It is a hard crust of salt spanning the tank with a void beneath, so the water below never touches salt. Break it gently with a broom handle from above, then remove the loose pieces before refilling.
The softener runs but the water is still hard. What should I clean first?
The injector and its screen in the control valve, plus the brine line and float. Blocked passages there stop brine being drawn, so the unit cycles through a full regeneration without ever recharging the resin.