Is It Safe To Use Soft Water In Pools & Hot Tubs?

🤝 Our content is written by humans, not AI robots. Learn More

Just installed a water softener and wondering whether it’s safe to use soft water in your swimming pool or hot tub?

We’ve shared the information you need to know in this guide.

📌 Key Takeaways

  • You shouldn’t use soft water in a pool or a hot tub.
  • Softened water may leach minerals from a pool and damage its structure, while hard water may deposit calcium minerals on your pool walls.
  • You should balance alkalinity, hardness, and pH in your pool or hot tub to prevent corrosion, scale buildup, and other damage, extending its lifespan.

🤔 Can I Use Soft Water In Pool Or Hot Tub?

No, you can’t use soft water in a pool or hot tub – you’ll need to treat the water to make it pool-suitable, first.

The ideal water in pools and hot tubs is not too hard or too soft.

swimming pool with tubes floating

Why shouldn’t you use soft water in a hot tub or pool?

Let’s first quickly recap what soft water is.

When water has little-to-no calcium minerals, it’s known as soft water. Naturally, most water supplies are moderately hard to very hard, and softened water is usually hard water that has been treated by a water softener, which removes its hardness minerals.

There are many benefits of soft water around your home. However, the problem with soft water in pools is that the water’s mineral balance is too low, which means the water is more susceptible to leaching from its surroundings.

Some of the issues that you may notice from using soft water in your hot tub or pool are:

  • Corrosion to shiny areas and metal parts
  • Corrosion so soft parts (in hot tubs)
  • Foaming issues

The only way to prevent these issues is to use a solution to balance alkalinity and hardness and bring up your pool’s pH level. We’ve shared more on the best ways to do this later in the guide.

Related: pH of Soft Water: Everything You Need to Know

Dark brown stains in shower

🔎 Is Soft Water Good For Swimming Pools?

If you’ve previously been using hard water in your pool, you’ll probably know already that hard water minerals aren’t good for pools.

Calcium hardness causes damaging scaling on your pool tiles, filters, and pipes – so surely soft water, being the opposite of hard, is good for swimming pools?

It’s not that simple.

👨‍🔧 Softened water has its own issues in pools and hot tubs. Because soft water is free from all minerals, it might attempt to balance itself by leaching calcium from the pool tiles and walls. This could damage your pool’s structure and lead to expensive repair work.

Undersaturated soft water is a little like acidic water. It’s missing minerals, which makes it more open to leaching minerals from its surroundings.

Plus, the sodium in softened water may also have corrosive effects.

If you want to protect your pool plaster, grouting, and metal parts (like railings and heaters) from damage and corrosion, don’t use soft water in your pool or hot tub.

📊 What’s The Ideal Water Hardness For Swimming Pools?

The ideal water hardness for pools and hot tubs is between 180 PPM (parts per million) and 200 PPM.

This is in the “moderately hard” range.

Most homes with hard water have a calcium hardness reading of 230 PPM to 350+ PPM. This is classed as “hard” to “aggressively hard”.

On the other end, if you use a water softener, it should eliminate your water’s magnesium and calcium content altogether. Your water hardness reading will be in the 0 PPM – 50 PPM range, classed as “soft”.

Neither of these hardness ranges is suitable for hot tubs and pools. If you have very soft or hard water, you’ll have to balance it before using it to fill your pool.

Pool water hardness test

📖 How To Keep Your Pool Water Hardness In Balance

Maintaining the calcium hardness in your pool or hot tub requires consistent water testing and adjusting when necessary.

Regularly Test Your Water

You’ll need to regularly test your water’s pH, calcium hardness, and alkalinity levels. You can buy a home test kit online or from your local pool supply store.

Most test kits are super easy to use – you just submerge a test strip in your pool water and wait for it to change color. You can then compare the color of the strip to the included color chart to learn about our water’s pH, hardness, and more.

Adjust Your Water Parameters

If your water’s hardness and alkalinity levels are off, you can take the appropriate steps to put them right. Maintaining your correct water balance will prevent damage to your pool or hot tub and extend the lifespans of your pool equipment.

If you discover your water is too soft, you can add a calcium hardness increaser, such as liquid calcium or calcium chloride dehydrate, to bring the hardness reading up. Remember, the ideal range for pool and hot tub water is 180 PPM to 200 PPM.

Water balancing treatments are quick to use. You usually just add them straight to your pool or hot tub and leave them to do their work.

Remember to add the product to your pool or hot tub whenever you refill it with a fresh batch of water.

If you’re unsure about the optimum hardness of your pool water, speak to a local pool expert.

Pool flocculant and other pool cleaning tools

❔ Can You Use Soft Water In A Pool? FAQ

What’s the difference between hard and soft water in a pool?

Hard water in a pool contains excess calcium and other minerals, while softened water is free from these minerals. Neither is ideal for a pool – hard water will form scale deposits on your pool walls and parts, while a softened water supply will gradually corrode your pool.

Is it better to use hard or soft water in a pool or hot tub?

Actually, hard and soft water are bad for a pool, so it’s not better to use any of these in your pool or hot tub water. You need to strike a balance between excess hardness and softness – achieving 180 PPM to 200 PPM is ideal for your water quality and pool health.

Can I use water softener salt in a pool or hot tub?

No. You can’t simply add softener salt to the hard water in your pool or hot tub to decrease its hardness. Salt can only be used to produce softened water in the presence of an ion exchange resin, so adding the salt will simply clog your filter with salt granules (potentially affecting water flow) and corrode surfaces inside your pool or hot tub.

Does soft water affect the pool chemicals?

We couldn’t find any evidence to suggest that soft water affects pool chemicals. The main issue with using softened water in your pool or hot tub is that it leaches minerals from the pool walls, weakening its structure. Plus, softened water is abrasive and may corrode your pool’s fittings, pipes, grouting, and glues.

  • Brian Campbell
    President & CEO, CWS, CWR

    Brian Campbell, a WQA Certified Water Specialist (CWS) and Certified Water Treatment Representative (CWR) with 5+ years of experience, helps homeowners navigate the world of water treatment. After honing his skills at Hach Company, he founded his business to empower homeowners with the knowledge and tools to achieve safe, healthy water. Brian's tested countless devices, from simple pitchers to complex systems, helping his readers find the perfect fit for their unique needs.

Scroll to Top