water softener in hot tub

Should I Bypass My Water Softener When Filling The Hot Tub?

If your water softener uses salt to soften the water, you should bypass it when filling your hot tub as the salt can corrode metal parts and shorten the hot tub's lifespan. If your softener uses potassium instead of salt, bypassing may not be necessary​.

Many hot tub owners ask whether they should bypass their water softener while filling their hot tubs. The question arises because of softened water’s potential impacts on the hot tub and its components. 

Soft water can cause some complications, but the choice to bypass your water softener is not always cut and dried. It depends on several factors, including the type of your water softener, the quality of your water, and the specific requirements of your tub. 

Don’t worry; I will discuss the topic in this blog and look for some viable alternatives to using softened water for your hot tub.

Should You Bypass Your Water Softener When Filling Your Hot Tub?

Softened water removes hardness minerals, like calcium and magnesium, and replaces them with sodium or potassium ions. 

This is a great process for reducing scale build-up in your home’s pipes and appliances. But it might not be the best choice for your hot tub. Here’s why:

  • Soft water can cause foaming: Sodium or potassium in softened water can react with the chemicals used in hot tubs and cause excessive foaming. This doesn’t look good, and you may need to change the water frequently
  • Soft water may damage components: Softened water can potentially lead to corrosion of the hot tub’s metal components and heater element. This could shorten the lifespan of your tub and lead to costly repairs.

However, using hard water directly can also cause problems, such as scale build-up in the tub and heater. This can similarly damage your hot tub over time. 

So, bypassing the water softener when filling your hot tub will largely depend on the balance of PH in your water.

How to Bypass a Water Softener?

If you decide to bypass your water softener when filling your hot tub, there are a few ways to do so.

1. Using a Bypass Valve

Most water softeners come with a bypass valve. With this bypass valve, you can redirect water flow around the softener unit when filling your hot tub. 

You need to switch the valve to the “bypass” position. It allows water to flow around the softener unit, delivering hard water directly from your supply.

2. Using a Separate Hose Bib

In some homes, the water softener may not have a bypass valve, or you prefer not to tamper with your softener settings. 

Hose Bib
Hose Bib

In this case, you could use a separate hose bib. It’s an outdoor water faucet that’s not connected to the water softener. This would allow you to fill your hot tub with hard water.

Alternatives to Softened Water for Hot Tubs

If you cannot bypass your water softener, or you’re looking for alternatives, consider these options:

Pre-treated Hot Tub Water: You can use the pre-treated water specifically for hot tubs. This water is already balanced, and you don’t have to make extensive chemical adjustments.

Portable Water Softeners: These are small, portable units that can soften water when you need them. You can adjust the level of softness to prevent the issues that come with overly softened water.

OTG3NTP3M Portable Water Softener

OTG3NTP3M Portable Water Softener

This portable STD water softener is an affordable, efficient solution for hard water issues. The unit has a high capacity, producing between 320 and 800 gallons based on the hardness of the water.

Balanced Water: This is the most crucial aspect of hot tub water care. Whether you use hard or soft water, you should regularly test and adjust the water to maintain the right balance of pH, alkalinity, and sanitizer.


Does softened water cause hot tub foam? 

Yes, the sodium or potassium in softened water can react with hot tub chemicals, causing foam.

Can I use hard water in my hot tub? 

Yes, but be aware that hard water can cause scale build-up, which can damage your hot tub and heater over time.

Is there a way to fill a hot tub without a water softener? 

Yes, you can use a bypass valve, separate hose bib, or use pre-treated water to fill a hot tub without a water softener. 

What are the disadvantages of using softened water in a hot tub? 

Softened water can cause excessive foaming and corrosion of the hot tub’s metal components. It might also not feel nice on the skin compared to hard water.

Which is better for a hot tub, soft water or hard water? 

Both have their own benefits and drawbacks. Soft water doesn’t leave behind minerals and deposits, which extend the life of your hot tub, but it can be more difficult to heat. On the other hand, hot water is easier to heat but can cause scale build-up and make it harder to clean.


So, deciding whether to bypass your water softener when filling your hot tub depends on various factors, including the type of water softener you have and the specific requirements of your hot tub. 

Before going to exist, I will suggest reading another guide to keeping your hot tub water crystal clear.



Hi, I'm Shimul, the founder of Pooltub Life. I'm excited about sharing the latest outdoor living trends with you. My goal is to provide you with up-to-date information that will help make your POOL & HOT TUB stylish and enjoyable. Read About Me More । Follow on Facebook

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