How to Add Salt to a Water Softener
Updated February 20, 2026
Pick the right salt, fill the brine tank correctly, break up salt bridges, and keep your water softener running so you get consistent soft water without the scale and spotty dishes.
Overview
Spotty dishes, soap that will not lather, and white scale creeping onto your fixtures -- that is your water softener telling you it is out of salt. This is the single easiest piece of plumbing maintenance you will ever do: 10 minutes and a $5-15 bag of salt. Your softener uses that salt to regenerate its resin bed, which is what actually strips calcium and magnesium out of your water. When the salt runs out, the resin cannot recharge, and hard water flows straight through to every faucet in the house. We see homeowners wait way too long to refill, so get on a monthly check schedule and you will never have an issue.
What You'll Need
Safety First
- Salt bags weigh 40 pounds. Lift with your legs, not your back, and keep the bag close to your body. If you have back issues, use a hand truck or pour from waist height instead of hoisting the bag over the top of the tank.
- Do not use rock salt (the type for melting ice on sidewalks). It is loaded with dirt, clay, and sand that will accumulate in the brine tank and eventually clog the brine valve. Stick to water softener-grade salt only.
Step-by-Step Instructions
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Choose the Right Type of Salt
You have three options here. Evaporated salt pellets are the best choice for most softeners -- 99.9% pure sodium chloride, dissolves cleanly, leaves almost no residue. They run $5-8 per 40-pound bag. Solar salt crystals are a step down at 99.5% pure, slightly more residue, and $4-6 per bag. Rock salt is the cheapest but we do not recommend it -- it contains dirt and insoluble grit that builds up in the brine tank over time. Spend the extra dollar or two and go with evaporated pellets. You will deal with far fewer problems down the road.
Tip: Check your owner's manual -- some high-efficiency softeners are designed specifically for pellets and will not work well with crystals. If you do not have the manual, evaporated pellets are the safest universal choice. -
Check the Current Salt Level
Pop open the brine tank lid and look inside. You want the salt at least a quarter full, ideally half. If you can see water sitting above the salt line or the tank is nearly empty, it is time to refill. Most households burn through one 40-pound bag every 4-8 weeks depending on water hardness and how much water you use. Before you add new salt, grab a broom handle and push it down into the salt. If it hits a hard crust and then drops through into empty space or water underneath -- you have a salt bridge. That needs to be dealt with before adding more salt (next step).
Tip: Do not wait until the tank is bone dry. If the salt runs completely out, your softener regenerates with plain water instead of brine, and the resin bed does not recharge. Hard water goes straight to your fixtures. Monthly checks prevent this entirely. -
Break Up Any Salt Bridge or Mush
A salt bridge is a hard crust that forms across the top of the salt with an air gap underneath. Everything looks fine from the top, but no salt is actually dissolving into the water below. Push a broom handle or stick into the salt in several spots to break through the crust. Be careful not to jab the sides or bottom of the tank -- you can crack the plastic or damage the brine valve. Salt mush is a different problem -- a sludgy layer of undissolved salt at the bottom, usually from lower-grade salt. Scoop it out with a plastic container and rinse the bottom of the tank with warm water.
Tip: Bridges happen more often in humid areas or when the softener sits near a heat source like a water heater or furnace. If you keep getting them, switch to evaporated pellets, keep the salt level at half full instead of topping it off, and check monthly. -
Add Salt to the Brine Tank
Pour the salt in and fill to about two-thirds -- not all the way to the top. That air space at the top reduces bridging. For a standard 18x33-inch brine tank, two 40-pound bags gets you right to that two-thirds mark. Close the lid and you are done. The softener handles the rest automatically -- it dissolves the salt during regeneration cycles and manages its own water level. You do not need to add water.
Tip: Do not mix salt types in the tank. Pellets and crystals dissolve at different rates, and mixing promotes both bridging and mushing. If you are switching types, let the current salt run down to near empty before adding the new stuff. -
Set Up a Maintenance Schedule
Check the salt level once a month -- just pop the lid and look. Most homes need to add salt every 4-8 weeks. Once a year, do a deeper clean: let the salt drop to near empty, scoop out any remaining salt and mush from the bottom, rinse with warm water, and refill fresh. While you are in there, check the brine valve and float assembly for buildup or debris. If your softener has a resin bed cleaner port, run a cleaner product ($5-10) through the system annually -- it keeps the resin's ion exchange capacity in good shape.
Tip: If your water starts feeling hard but the salt level looks fine, check for a bridge first. No bridge? Try hitting the manual regeneration button (most units have one). If that does not fix it, the resin bed may be worn out -- they typically last 10-15 years before needing replacement.
Pro Tips
- On a sodium-restricted diet? Potassium chloride works in any water softener as a direct swap. It costs 3-4 times more, but you get softer-tasting water with no saltiness, and it is better for watering plants. The only downside is cost.
- Salty-tasting water usually means your softener is using too much salt per regeneration cycle. Check the salt dose setting on the control panel -- it may be set higher than your actual water hardness requires. A $15-30 home water test kit tells you exactly what your hardness level is so you can dial it in.
- Store salt bags on a pallet or piece of plywood, never directly on a concrete basement floor. The bags wick moisture right through the concrete and the salt hardens into a solid block inside the bag. We see this all the time.
- If your softener is 15+ years old and constantly bridging or producing hard water despite having plenty of salt, the resin bed is probably depleted. A water treatment specialist can test it and swap the resin for $200-400 -- way cheaper than replacing the whole unit.
- Got a vacation home? Run a manual regeneration cycle before you leave and another when you come back. This keeps fresh brine in the system while you are away and flushes stagnant water from the resin bed before you start using it again.
When to Call a Pro
You will never need a pro just to add salt. But call a water treatment specialist if the softener is not producing soft water despite having plenty of salt (could be resin replacement, valve repair, or reprogramming), if the brine tank is overflowing with water (brine valve or float issue), if you need your water hardness tested to set the softener correctly, or if the control valve is leaking.