How Often Should You Change Cold Plunge Water?

March 14, 2025 4 min read

Maintaining clean and sanitary water in your cold plunge tub is essential for both health and performance. But how often should you change cold plunge water? The answer depends on several factors, including your plunge frequency, filtration system and whether you use an ozone generator for cold plunge sanitation.

In this guide, we’ll break down cold plunge water maintenance, the best practices for keeping your water clean, and how to extend water life while minimizing maintenance costs.

How Long Can You Keep Water in a Cold Plunge?

Without proper maintenance, cold plunge water can become cloudy, develop bacteria, and collect debris. A good rule of thumb is:

No filtration or sanitation – Change water every 3–5 days
Basic cold plunge filtration systems – Change water every 2–4 weeks
Ozone generator & UV purification – Change water every 4–8 weeks
Cold plunge chiller + filtration – Change water every 6–8 weeks

Using a cold plunge filter, an ozone generator and a water chiller with built-in filtration can significantly extend the life of your water.

Factors That Affect Cold Plunge Water Longevity

1. Frequency of Use

The more often you cold plunge, the more contaminants (sweat, oils, and bacteria) build up. If you plunge daily, you’ll need a high-quality cold plunge filtration system to keep water clean for longer.

Daily plunging - Consider a high-flow filter and ozone system.
Plunging 1–2 times a week - You can likely go longer between water changes.

2. Filtration System

A cold plunge water filter is one of the best ways to extend the life of your water.

Basic inline filters: Remove debris and particles.
Activated carbon filters: Reduce organic contaminants and chlorine.
Cold plunge-specific filtration systems: Designed to work with water chillers and ozone systems.

➡ Need a filter? Check out the best cold plunge filtration systems for stock tanks and DIY builds.

3. Ozone & UV Purification

Adding an ozone generator for cold plunge sanitation can drastically reduce bacteria and extend water cleanliness by weeks.

Ozone generators break down contaminants at a molecular level.
UV lights kill bacteria, viruses, and algae without chemicals.

➡ Looking for an ozone system? Learn more about Cold Plunge Ozone Generators .

4. Water Temperature

Colder water naturally slows down bacterial growth. If your water is consistently below 50°F (10°C), it will stay cleaner longer. Warmer water (>60°F) promotes bacteria and algae growth, requiring more frequent changes.

Tip: Pairing a cold plunge chiller with a filtration system keeps water fresh for up to 8 - 12 weeks.

➡ ️ Check out the best cold plunge chillers for maintaining water temperature.

5. Outdoor vs. Indoor Use

Outdoor cold plunges are exposed to leaves, bugs, dirt, and UV rays, accelerating water contamination.
Indoor cold plunges in climate-controlled environments generally require fewer water changes.

Tip: If your cold plunge tub is outside, consider a cold plunge cover to protect it from debris.

➡ Shop cold plunge covers here.

Best Practices to Keep Cold Plunge Water Clean Longer

Shower Before Plunging: Rinsing off sweat, oils, and lotions before getting into your cold plunge tub helps reduce water contamination.
Use a Water Filter: Installing a cold plunge filtration system removes debris and particles that can make your water dirty.
Add an Ozone Generator: An ozone generator continuously sanitizes the water, reducing the need for frequent water changes.
Keep Your Water Cold: Using a cold plunge chiller keeps temperatures below 50°F, slowing down bacterial growth.
Clean the Tub Weekly: Even with filtration, it’s a good idea to:

Wipe down the inside walls to remove biofilm buildup.
Rinse or replace your filter cartridge every 1–2 weeks.

Step-By-Step: How to Change Cold Plunge Water

When it’s time to change your cold plunge water, follow these steps:

1. Drain the Tub

If your cold plunge tub has a built-in drain, open it to release the water.
If not, use a submersible pump to drain water quickly.

2. Scrub the Interior

Use a soft cloth or sponge with mild soap or vinegar.
Avoid harsh chemicals that could damage the tub or irritate skin.

3. Rinse Thoroughly

Flush the tub with fresh water to remove any residue.

4. Refill with Fresh Water

Fill the tub with clean water and let it cool naturally or use a cold plunge chiller.

5. Add Filtration & Ozone

Install your cold plunge filtration system and turn on your ozone generator to maintain water clarity.