Water Softener Maintenance Checklist and Which Salt to Buy

A salt-based softener needs very little care, but the little it needs matters. If the brine tank runs dry or the salt crusts over, the resin never gets recharged and hard water goes straight into your pipes and water heater. Here's what to check, how often, and which salt to put in the tank, based on extension guides and softener makers' own manuals. Your unit's manual always wins if it says something different.

The checklist

How often	What to do	Why
Every 2 to 3 weeks until you know your usage, then on that rhythm	Lift the lid and look at the salt level. Morton's manual says to add salt when it's under 1/4 full.	When the salt runs out, the softener can't make brine and you get hard water.
Each time you add salt	Break up any crust stuck to the tank walls, and push a broom handle straight down to feel for a salt bridge (see below).	A bridge leaves a hollow gap above the water, so no brine forms even though the tank looks full.
Now and then, more often in humid weather	Keep salt about half full rather than topped off, and stir it with a blunt tool.	Morton says bridges usually come from high humidity, the wrong salt, an overfull tank, or long gaps between recharges. Its manual says humid areas should keep the level lower and refill more often, which applies to garages in Tampa Bay.
At least once a year	Inspect and clean the brine valve and float assembly, and check the brine tank for buildup.	Nebraska Extension recommends cleaning and inspecting the brine valve and float at least yearly.
When sludge or scale shows up in the brine tank, or after a long vacation	Empty and clean the brine tank. Your manual will say how; NDSU notes many manuals use a bleach rinse.	Both NDSU and Nebraska say how often depends on the type and purity of salt and your water.
Periodically, and after any repair	Retest the softened water for hardness (strips or a drop kit, see testing your water).	Nebraska Extension recommends periodic retesting to confirm the equipment still works.
If you notice it, any time	Salt use jumps or hard water returns: have a service provider check the settings.	Nebraska Extension's advice when an automatic or demand unit uses more salt than expected or stops softening.

Which salt to buy

Nebraska Extension says to follow your softener maker's recommendation, and that most softeners are designed for compressed salt (pellets, nuggets, or beads). Morton recommends salt that is 99% or more pure, with less than 1% impurities, and labeled for water softeners.

Salt type	What it is	Use it?
Evaporated salt pellets	Salt dissolved and re-evaporated, then pressed into pellets. Morton calls evaporated salt the purest form (99.99% sodium chloride).	Yes. The usual default; least insoluble residue.
Solar salt (crystals or pellets)	Sea water evaporated by the sun. WaterTech says many solar brands are about 99.6% pure.	Yes, Morton lists it as recommended. WaterTech says it may not work as well as evaporated salt at very high hardness.
Iron-fighting pellets (for example Morton Rust Defense)	Pellets with an additive; Nebraska notes iron products may contain food-grade additives such as citric acid.	Worth considering on well water with some iron, if your softener maker allows it.
Potassium chloride	Sodium-free alternative.	Only if you need to cut sodium. NDSU says it costs more (up to about $25 per 40 lb bag vs about $5 to $10 for regular salt) and about 10% more is used per regeneration.
Block salt	Large pressed blocks.	Only in units designed for blocks, and never livestock blocks, which Nebraska says may have incompatible additives.
Rock salt	Mined salt with more insoluble minerals.	Generally no. Nebraska says only if your manufacturer suggests it and it averages under 1% impurities; Morton and WaterTech advise against it because of sludge and bridging.
Ice melt, pool salt, table salt, ice-cream salt	Not made for softeners.	No. Morton doesn't recommend any of them.

How to find and break a salt bridge

Hold a broom handle next to the softener and mark the height of the tank rim on it.
Push the handle straight down into the salt. If it stops on something hard before your mark reaches the rim, Morton says it's most likely a bridge.
Push into the crust in several places to break it. Never use anything sharp or pointed, and don't pound on the outside of the tank; both can damage it.
If it's solid, Morton's fix is to scoop out loose salt, pour 2 to 3 gallons of hot tap water into the brinewell, wait 45 to 60 minutes, run a manual recharge, then break up what's left. Repeat as needed.

When it's more than routine

Iron in the water. Nebraska Extension says high iron or manganese can reduce the resin's capacity, so the resin may eventually need cleaning or replacement, and iron above about 5 ppm or hydrogen sulfide calls for treatment before the softener. Talk to a water treatment pro.
Backwash too short. Nebraska says the backwash should run long enough that the drain water runs clear.
Septic systems. Nebraska estimates each regeneration uses about 50 gallons of water, which adds load to a septic system.

Questions to ask before you sign a service plan

"What exactly does a service visit include: brine valve and float cleaning, settings check, hardness test, resin check?"
"Which salt does the manufacturer specify for this unit?"
"Is the unit demand-initiated, and what salt dose and capacity is it set to?" (See the sizing guide.)
"Can I do the routine checks myself without voiding the warranty?" Get the answer in writing.

Coming soon: where to buy softener salt and hardness test strips.

Sources

Wondering if you need salt at all? Read salt vs salt-free

Live in Tampa Bay? Request softener quotes from local installers →