A water softener not using salt is usually blocked by a salt bridge, a hard crust that leaves a hollow above the water so no brine forms. The other common causes are salt “mush” at the bottom of the tank, a valve that isn’t regenerating, a plugged injector or brine line, a tank that isn’t refilling, or the bypass valve being left open. Check them in that order: the first two take minutes and need no tools.
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First, rule out the one case that isn’t a fault. A small household on moderately hard water uses very little salt: one person on 5 gpg water goes through a 40 lb bag in roughly 11 months with an efficient softener, by our calculations in how long a bag of softener salt lasts. If your water still tests soft, a slow-moving salt level may be normal.
If the water is turning hard (spots, scale, poor lather) and the salt level hasn’t moved, work through the causes below.
Quick diagnosis table
| What you see | Likely cause | Section |
|---|---|---|
| Tank looks full, salt level never drops, hard water | Salt bridge | 1 |
| Sludge at the bottom, water level high | Salt mushing | 2 |
| Display blank or clock wrong, no regeneration noise at night | Not regenerating | 3 |
| Brine level doesn’t drop during regeneration | Valve not drawing brine | 4 |
| Tank bottom dry after regeneration | Not refilling | 5 |
| Hard water and softener silent | Bypass valve open | 6 |
| Salt drops, but water still hard | Wrong setting, resin or iron problem | 7 |
1. A salt bridge
Culligan describes a salt bridge as salt caking into a hard mass that makes the tank look full while an empty space sits underneath. The water below can’t reach the salt, so the brine is too weak and the resin isn’t recharged. It notes that solar salt is the type most prone to bridging (see softener salt types).
How to check: push a broom handle (or a length of plastic pipe) gently straight down into the salt. If it stops on a hard layer and then breaks through into a gap, you’ve found a bridge.
How to fix it:
- Put the softener into bypass, so no water is drawn while you work.
- Break the crust with the broom handle, working round the tank. Don’t stab hard at the walls or the brine well, which is the narrow tube inside the tank.
- Scoop out large chunks if they won’t fall, and let the broken salt drop into the water.
- Wait a couple of hours for brine to form, return the valve to service, and start a manual regeneration. Pentair’s manual notes that settings and fixes only take effect at the next regeneration unless you start one yourself.
- Test the water a day later.
To stop it coming back, keep the tank around half full rather than topped to the lid (Culligan’s advice is to check monthly and add salt when it drops below about half), and break up any crust you feel when adding salt.
2. Salt mushing
Mushing is the opposite problem: salt dissolves and recrystallises into a dense sludge at the bottom of the tank. Culligan notes that pellet salt is more prone to it, and that like bridging it leads to poor regeneration. Mush can also block the brine line intake.
How to fix it: there’s no quick break-up for mush. Bypass the softener, let the salt run low, then scoop or siphon out the sludge and water, rinse the tank and refill with fresh salt. If the mush has reached the brine well or the valve, call the installer.
3. The softener isn’t regenerating
A softener only uses salt when it regenerates. Pentair’s troubleshooting guide lists the reasons a unit fails to regenerate: a problem with the electrical supply (check the fuse and transformer), the control not being set properly, or a failed drive motor, flow meter, circuit board or microswitch.
What you can check yourself: is the display on and the clock right? A power cut can reset the time so the softener regenerates at mid-afternoon or not at all. Pentair’s default regeneration time is 2:00 a.m., when little water is used. Check that the hardness, salt and days-override settings haven’t been wiped. Then start a manual regeneration and listen: you should hear water moving and see the brine level fall during the brine stage. If nothing happens, the fault is in the control or motor.
4. The valve isn’t drawing brine
If the softener cycles but the brine level doesn’t drop, it isn’t sucking brine out of the tank. Pentair lists the causes: water pressure below 20 psi, a plugged injector or injector filter, a restricted drain or brine line, a leak in the brine line, or too little water in the brine tank.
What you can check: look for kinks in the brine line and drain hose, and make sure the drain hose isn’t raised too high or blocked at its outlet. Check that the house pressure isn’t unusually low. The injector is a small part in the valve that can clog with sediment; the manual shows how to remove and clean it, but if you’re not comfortable taking the valve apart, it’s a short service call.
5. The brine tank isn’t refilling
After regeneration, the valve sends a measured amount of water back into the tank to dissolve salt for next time. Pentair lists a blockage in the brine line or brine valve, and a missing, wrong or plugged refill flow control as causes. No water in the tank means no brine, however much salt is sitting there.
6. The bypass valve is open
It sounds obvious, but it’s the first item on Pentair’s list for hard water at the taps. Bypass is used for outdoor watering, plumbing work and leaks. If someone left it in bypass, water skips the softener entirely: the salt never moves and the water is hard. Check that the bypass handles are in the “service” position.
7. Salt is being used but the water is still hard
This is a different problem. The usual causes are a hardness setting lower than your real hardness, a change in your water supply, heavy water use, or resin that’s worn or fouled with iron. Pentair suggests checking the regeneration frequency, adjusting the hardness setting, and cleaning the resin bed if mineral or iron builds up. Our guide to the water softener hardness setting shows how a setting that’s too low lets hard water through for days at a time.
How much salt should it be using?
Once it’s working, compare with what an efficient softener should use. A family of four on 10 gpg water uses about 349 lb a year, roughly 29 lb a month. Our guide to how much salt a water softener uses has the full table and the effect of the salt setting. You can also put your own numbers into the calculator:
This calculator needs JavaScript. Salt per year (lb) = people × 80 × hardness (gpg) × 365 ÷ 3,350.
Frequently asked questions
How do I know if my water softener is working?
Test the softened water with a hardness strip, ideally just before a scheduled regeneration. It should read close to 0 gpg. Scale and spotting coming back are the everyday signs that it isn’t.
Should there be water in the brine tank?
On most softeners, yes: a few inches of water at the bottom, below the top of the salt. Pentair lists both “excessive water” and “fails to refill” as faults, so far too much or none at all are both signs of a problem.
How often should I check for a salt bridge?
Whenever you add salt, and at least monthly, which matches Culligan’s advice for checking the brine tank. A quick push with a broom handle is enough.
Why does my softener use salt in some months and not others?
A demand-initiated softener regenerates after a set volume of water, so salt use follows water use. Guests, holidays and summer watering on softened water all change it.
Should I regenerate before going away?
Morton suggests running a manual regeneration before an absence of three weeks or more, to avoid discoloured water from iron when you return.
