Guides · Twin Cities homes
How much salt should my water softener use, and which kind?
The short answer
On typical Twin Cities hardness of 15 to 25 grains, a family of four uses roughly one 40-pound bag of salt a month. Keep the brine tank about half full, use pellets or solar crystals rather than rock salt, and pay attention if usage suddenly stops — a softener that isn't eating salt isn't softening.
How much salt is normal
Salt use depends on your water hardness, how much water the household uses, and the softener's efficiency. As a working rule for the metro's hard water: a modern, correctly sized softener for a family of four runs through about a 40-pound bag a month — more in a big household or on very hard water like Maple Grove's 25-plus grains, less on softened city supplies like St. Paul's. An old or oversized unit can use two or three times that for the same result.
Not sure what your city's hardness is? The free Loon WaterIQ report has it, from your city's own data.
Which salt to buy
- Evaporated pellets (the 99.9% pure bags) — the cleanest option, leaves the least residue in the tank, worth the small premium.
- Solar crystals — fine for most softeners, slightly more insoluble material than pellets.
- Rock salt — the cheapest and the dirtiest. It leaves sediment that gums up the brine tank over time. Skip it.
- Potassium chloride — the sodium-free alternative if you're on a restricted diet or you water plants with softened water. Works the same; costs more; needs a slightly higher setting on most softeners.
How full to keep the tank
About half full is the sweet spot. Filling to the brim invites a salt bridge — a hard crust that forms across the top of the tank while a hollow opens underneath. The tank looks full, the softener finds no salt in the water below, and your water quietly goes hard. If the salt level hasn't dropped in weeks, take a broom handle and gently push straight down; if it breaks through a crust, that was a bridge.
"My softener isn't using any salt"
That's the most important symptom on this page. A softener that stops consuming salt has stopped regenerating, which means it has stopped softening — you'll notice spots on glasses and scale on faucets creeping back. Causes, roughly in order: a salt bridge, a clogged brine line or injector, a control valve that's lost its schedule (often after a power outage), or a resin bed that's finally worn out. The first two are quick fixes. The last one means the softener is done. Most units have a 10-to-15-year life, and the resin is what ages.
Try it yourself, or call?
Worth trying first
- Break a suspected salt bridge with a broom handle and let the tank run down before refilling
- Check the control head for a lost clock or schedule after a power outage
- Switch to pellets if you've been using rock salt, and clean the sludge out of the brine tank
Time to call
- The softener uses no salt and hardness symptoms are back — we test the softened water in minutes and tell you whether it's a fix or a retirement
- Salt use has jumped with no change in the household — it's regenerating too often, wasting salt and water
- The unit is past 12 years and you'd like an honest read on it before spending on repairs
Common questions
Does softened water taste salty?
Not noticeably. A softener adds a small amount of sodium in proportion to the hardness it removes — on very hard water, that's still far less than a slice of bread. If sodium is a medical concern, potassium chloride pellets remove it from the equation, or we can leave a hard-water tap for drinking.
Can I use pool salt or water-conditioner salt?
Please don't. Pool salt and de-icing salt aren't purified for softeners and can foul the resin. Use only salt labeled for water softeners.
Should the softener be regenerating every night?
Not on a modern demand-initiated unit — it should regenerate based on water used, typically every few days for a family. A softener regenerating nightly on a timer is probably an older model wasting salt and water. Worth a look.