Can You Use Pool Salt in a Water Softener?

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Wondering whether pool salt is safe to use in a water softener? Check out our answer in this short guide.

📌 Key Takeaways:

  • It’s safe to use a small amount of pool salt in your water softening system.
  • However, we don’t recommend using pool salt instead of water softener salt permanently because pool salt is dense salt with fine grains and is more likely to form salt bridges and reduce the effectiveness of brine draw.

🔎 Is It Safe To Use Pool Salt In A Water Softener?

Yes, you can safely add small amounts of pool salt to your water softener brine tank. If you’ve accidentally bought pool salt instead of softener salt, you should be able to safely feed the pool salt into your water softener tank along with the softener salt.

However, you shouldn’t permanently replace your water softener salt with pool salt because using large amounts of pool salt will increase the likelihood of salt bridge formation and prevent your softener from effectively drawing brine during the regeneration process.

The takeaway?

It’s safe to use small amounts of pool salt alongside water softener salt in the brine tank. But don’t exclusively use pool salt in your softener.

Water softener salt bridge

🤔 What Happens If You Put Pool Salt In A Water Softener?

If you put pool salt in a water softener tank, the following things might happen:

Increased Risk Of Salt Bridging

Water softening salts are specifically designed for use in water softeners, while pool salt should be added to swimming pools.

If you decide to use pool salt in your water softener system, the salt is more likely to cause mushing (when the salt clogs the bottom of the tank and is unable to dissolve) and bridges (when the salt forms a hard, compact layer over the rest of the salt).

Salt mushing and bridging can both prevent salt from dissolving into water to form brine, and mushing may also block the brine draw pipe and prevent proper regeneration.

Reduces Brine Draw Efficiency

Pool salt is much finer than water softener salt. The pool salt’s grains are more closely packed together, and their high density affects water’s ability to flow through the salt in the tank.

This can be a problem during the brine draw cycle in the regeneration process. When a water softener regenerates, it draws brine out of the salt tank, diluting it at the same time with fresh water.

If the brine solution can’t be drawn quickly enough out of the tank, the brine that does get drawn might be too diluted, making it less effective at replenishing the sodium ions in the softening resin.

Standing water in water softener salt tank

Excess Salt In Resin Tank

Having densely packed salt in the softener tank may also cause the salty water solution to be drawn for an extended period of time as the water softener struggles to get what it needs, resulting in an overload of salt in the softener resin.

Usually, the final stages of regeneration would involve flushing the salt water out of the resin tank once the resin beads were replenished with sodium. However, this might happen concurrently with the brine draw, meaning that as salt water is being flushed out of the tank, the softener continues to draw brine into the tank.

Having too much salty brine in the resin tank could affect the quality of your soft water, and you might even notice an unusually salty taste.

Clogged Water Softener Valve

Water softener salt dissolves in water in the brine tank, forming a salty water solution. As this happens, the salt particles shrink – but these particles start off fairly large, which prevents them from being drawn into the water softener’s control valve.

Salt for swimming pools, on the other hand, is much smaller to start with. When fine pool salt dissolves in water, the crystals are more likely to be drawn into the water softener valve, where they could accumulate and eventually clog the valve.

You can usually resolve this issue by periodically flushing the valve, but in a worst-case scenario, you might have to replace the entire valve.

Water softener control float valve clogged with salt

📑 So, Can You Use Pool Salt In A Water Softener? Final Word

As long as your swimming pool salt is high-purity and as free as possible from tiny particles of dirt and debris, you should be able to safely use it in place of softener salt in your softener tank.

However, it’s always best to use water softener salt, since this salt type is specifically designed for use in water softeners, with a reduced likelihood of clogging, bridging, and other issues affecting a water softener’s performance.

If you’ve accidentally added salt for pool water to your softening system, don’t panic. There’s no need to remove the salt – just wait for the salt level in the tank to drop, then top it up with softener salt. As long as the pool salt doesn’t dominate the tank, you should be fine.


Is pool salt different from water softener salt?

Yes, pool salt is different from water softener salt. Both products are made from sodium chloride. However, pool water salt (intended for use in a swimming pool) has smaller salt crystals and is more densely packed, while water salt for water softeners may be salt crystals or pellets and usually has larger particles. Plus, water softener salt usually has additives that prevent iron buildup in the softener tanks and keep the system clean.

Can I use water softener salt in my pool?

We don’t recommend that you use water softener salt in your pool. You might think, “Surely the type of salt in my pool is unimportant.” But actually, water softener salts are known to have additives that could damage your pool equipment. It’s always best to exclusively use pool salts in your pool water, just as you should exclusively use water softening salts in your water softener.

Can you use Morton pool salt in your water softener?

Yes, you can technically use Morton pool salt in your water softening system. However, adding salt of a different variety to your tank may affect your softener’s performance and the quality of your softened water. To avoid issues with brine draw and clogging in the salt tank, we recommend using Morton’s softener salt pellets instead of pool salt in your softener.

Can you use driveway salt in water softener?

No, you shouldn’t use a type of driveway salt (usually rock salt) in your water softening system. Driveway salt is often high in impurities, which could clog the softener, affect regeneration efficiency, and increase your cleaning duties.

  • Jennifer Byrd
    Water Treatment Specialist

    For 20+ years, Jennifer has championed clean water. From navigating operations to leading sales, she's tackled diverse industry challenges. Now, at Redbird Water, she crafts personalized solutions for homes, businesses, and factories. A past Chamber President and industry advocate, Jennifer leverages her expertise in cutting-edge filtration and custom design to transform water concerns into crystal-clear solutions.

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