Water Softener Not Working? Common Problems and How to Fix Them

The most common reason a water softener stops producing soft water is that it has run out of salt. This sounds obvious, but the salt level can be difficult to judge from the top of a brine cabinet — it is worth actually looking in. The brine tank should have salt in it at all times. If the tank is empty, top it up and initiate a manual regeneration cycle if your unit has that option. The softener should return to normal function within a day or two once salt is restored.

If the salt level looks adequate but you are getting hard water, check whether the salt has formed a bridge — a crust across the top of the tank that prevents salt below from dissolving. Push a broom handle down through the salt to break up any bridge. See our dedicated guide on salt bridges for a full explanation.

Every water softener installation includes a bypass valve that diverts water around the softener — useful during servicing or if the unit needs to be isolated. If someone has opened the bypass valve and not closed it again, hard water will be flowing through the house without passing through the softener at all.

Find the bypass valve (usually a lever or turn valve on the softener's inlet/outlet pipework) and confirm it is in the service (not bypass) position. This is a surprisingly common cause of sudden hard water, particularly after a service visit or plumbing work nearby.

If the resin is exhausted and the unit is not regenerating, the causes are usually: a timer or programming fault on electric units (check the control head clock — power cuts reset many units to midnight), a failed brine draw component (injector or seal), or the brine tank is dry and there is no brine to draw.

On electric metered units, check the control head display for any error codes — consult your manual for their meaning. Many faults are reported as specific error numbers that point directly to the affected component. Initiating a manual regeneration cycle (if the unit supports it) can confirm whether the cycling mechanism itself is working.

If the brine tank is full of water after a regeneration cycle, the brine is not draining properly. This is usually caused by a blocked or failed brine injector (venturi), a kinked or blocked drain line, or a failed float valve in the brine tank allowing overfilling.

A blocked injector is a common service item — the small venturi nozzle that draws brine into the resin tank gets clogged with salt residue over time. It can usually be removed and cleaned with warm water and a small brush. If the problem recurs, injector replacement is inexpensive.

Call a service engineer when: you have checked salt levels, the bypass valve, and the programming, and the unit still produces hard water; the brine tank overfilling problem persists after cleaning the injector; you see visible water leaking from the unit or from pipe connections; or the control head shows a fault code you cannot diagnose from the manual.

Most reputable UK water softener suppliers offer a call-out service. For units outside warranty, independent water treatment service engineers can often attend more quickly and at lower cost than the original manufacturer's service team.