Can You Overfill A Water Softener With Salt? Yes, You Can!

UPDATED: January 9, 2023

You just got back from the hardware store with several bags of water softener salt and you really don’t want to lift those bags any more than you absolutely have to, so you want to add as many as you can to your water softener brine tank. But can you overfill your water softener brine tank with too much salt?

Overfilling a water softener brine tank with salt can encourage salt bridging which is when the salt at the top of the brine tank sticks together and does not drop down the tank as the salt underneath is used which means that your water softener will run out of salt but it will appear full.

Filling your water softener brine tank to the correct level and replenishing the salt before it gets too low is very important. Once you understand why the amount of salt in your water softener brine tank can affect your water softeners’ performance, you will know when to add salt, and how much to add.

How much salt should you put in your water softener brine tank?

As a basic rule of thumb, I always recommend that you keep the level of salt in your water softener brine tank between 1/3 and 2/3 full.

The reason for this is that in most cases, a water softener will need the salt level in the brine tank to be at least 1/3 full in order for it to create the amount of brine that the water softener needs to regenerate the water softener resin inside of the water softener.

Check out this short video of how a water softener regenerates water softener resin.

When the salt level in the water softener brine tank goes below 1/3 of the tank, the brine may not be strong enough to regenerate the water softener resin.

Because the brine from the brine tank gets diluted as it runs through the water softener resin, it needs to be at full strength in order to regenerate the water softener resin efficiently.

NEVER, EVER let your water softener brine tank run out of salt!

What Happens If My Water Softener Runs Out Of Salt? Solved!

This will lead to hard water stains throughout your home, and if you have iron in your water that your water softener normally removes, you will get orange iron staining wherever your water settles on a surface which can be a major hassle to clean.

Also, letting your water softener run out of salt can cause the brine tank to become full of water which could overflow when adding new salt to the tank.

Why adding too much salt to your brine tank can cause a problem.

Salt Bridging!

This is the primary reason that you should not overfill your water softener brine tank.

A salt bridge is when the salt towards the top of the water softener brine tank bonds together, creating a crust that stays suspended at the top of the brine tank.

How Do I Clear A Water Softener Salt Bridge?

Humidity in the air can cause a small amount of salt to dissolve on the outer surfaces of the salt in the brine tank which can cause two pieces of salt to bind together. If enough pieces of salt bind together, they will create a crust, which will not drop down as the salt underneath is used.

The closer the level of salt gets to the top of the brine tank, the more likely salt bridging can occur because the humidity can change more when the air is closer to the opening of the tank, and there is more opportunity for the salt to cling to the side of the tank.

Inside a water softener’s brine tank is a white tube that has a brine float assembly inside of it. The top of this tube has a flat cover on it which makes for great support for a salt bridge.

Salt that sits on top of this flat cover can be exposed to fluctuating humidity which can cause any salt that sits on the top of it to bond together and as more salt bonds to this supported block of salt, a salt bridge can form.

If you have ever seen salt clinging to the sides of a salt shaker where you have to bang on the salt shaker to break up the salt inside of the shaker, you understand how salt can cling together to create a salt bridge.

At what point do you need to add salt to your water softener brine tank?

Over time, you will get into a routine where you will just know when it is about time for you to add salt to your brine tank.

But until you get to that point, you should check your water softener brine tank at least once a week unless your water softener installer tells you exactly how much salt you will be using based on how often your new water softener will be regenerating.

By checking your water softener brine tank weekly, you will get a good idea of how much salt you are using on a regular basis and you will get into a routine of adding salt to your brine tank often and not get into the habit of overfilling your brine tank.

After a while, you may decide that you only have to check your water softener brine tank once a month because you are not using enough salt to justify checking your brine tank weekly and that is fine.

The important thing is that you are checking your water softener often enough that you are not letting it get too empty before adding salt.

Add salt to your brine tank when the level of the salt is about 1/3 of the way up the tank. I like to tell water softener owners to consider their water softener brine tank to be empty at 1/3 of a tank, and full at 2/3 of a tank.

This way you should never let your water softener run out of salt, and if you fill the tank a little bit over 2/3 of a tank, it will still not be overfilled where it could cause any problems with salt bridging.

You should never let your water softener run out of salt, but that does not mean that it is ok to overfill the water softener brine tank with salt just so you don’t have to check it often enough.

What Happens If My Water Softener Runs Out Of Salt? Solved!

Make checking your water softener brine tank a group effort if it is hard for one person to keep an eye on it, there is no reason to overfill your water softener brine tank if several people are making sure that it has enough salt in it.