A softener presents as two tanks and a plastic head, and inside that are six components with distinct jobs and distinct ways of going wrong. Learning which is which is worth doing, because the great majority of softeners reported as broken have a fault in a cheap part rather than in the resin everybody suspects first.
Resin tank, riser and distributor
The tall fiberglass vessel holds the ion exchange bed that does the softening. A riser tube runs down its center to a slotted distributor at the base, which collects softened water while keeping beads in the tank. Resin degrades slowly with chlorine and quickly with iron, and a bed left unregenerated for months compacts. If beads appear in the household plumbing, the riser or distributor has broken and the tank has to be opened: new media alone will not fix that.
Brine tank, float and safety valve
The brine tank holds salt and makes the concentrated solution that recharges the resin. Its float assembly and safety valve limit how much water enters, and a stuck float is one route to a brine tank overflowing onto the floor. The characteristic failure here is a salt bridge: a hard crust across the tank with an air gap beneath, so water below never contacts salt, no brine is made and the water stays hard while the cycle looks perfectly normal.
Control valve, injector and lines
The control head directs flow in service and runs the regeneration sequence, and it is where most puzzling behavior originates, since its seals and pistons wear and its programming can be lost. The injector, a small venturi nozzle in the head, creates the suction that draws brine across, and it is the single most common failure on a softener because it blocks with salt residue and sediment. The brine and drain lines must be free of kinks with a proper air gap at the drain.
Reading a symptom back to a part
Hard water with normal salt use points at the injector or a salt bridge. Salt not being used at all points the same way. Water standing high in the brine tank points at the float, the injector or a blocked drain line. Continuous flow to drain points at worn control valve seals. Beads in the plumbing means the riser or distributor. And hard water with the unit apparently perfect very often means the bypass valve was left open. Our softener parts guide covers replacement against a whole unit.
Questions people ask about parts of a water softener
Which part fails most often?
The injector. It blocks with salt residue, so no brine is drawn and the resin is never recharged while the cycle appears normal.
What is a salt bridge?
A hard crust across the brine tank with an air gap beneath it, so water never contacts the salt and no brine solution is made.
Beads are coming out into my taps, what broke?
The riser tube or the bottom distributor inside the resin tank. That needs the tank opening and is not fixed by new media.
The softener seems fine but water is hard, why?
Check the bypass valve position first, then the brine tank for a bridge, then whether brine is actually being drawn.