Cold Plunge Maintenance: How to Keep Your Water Clean

If you're using a Cold Pod, Ice Barrel, or any tub without built-in filtration, water management is straightforward: fill, use, treat, and change regularly.

After each session: Add 1/4 cup of 3% hydrogen peroxide per 100 gallons. It's cheap ($3 at any drugstore), breaks down into water and oxygen, and kills bacteria without leaving chemical residue on your skin. Alternatively, use 1-2 tablespoons of bromine granules.

Every 3-7 days: Drain and refill with fresh water. In hot weather or with daily use, lean toward 3 days. In cold weather with occasional use, 7 days is fine. If the water looks cloudy or smells off, change it immediately regardless of schedule.

Weekly: Wipe down the interior walls with a mild cleaning solution. Rinse thoroughly before refilling.

Tubs like the Plunge and Arctic Warriors have built-in circulation and filtration systems. These are game-changers for water longevity — clean, treated water being circulated and filtered can last 2-4 weeks without a full change.

The Plunge's ozone system is particularly effective. Ozone kills 99.9% of bacteria on contact and breaks down naturally, leaving no chemical taste or smell. If your tub has ozone, you need minimal additional treatment.

For chiller tubs without ozone: maintain a small residual sanitizer level. Bromine works better than chlorine in cold water because chlorine becomes less effective below 60°F. Test strips ($8 for 100) let you check levels in seconds.

Using a cover when your tub isn't in use prevents 80% of maintenance headaches. It keeps out debris, insects, dust, and UV light (which breeds algae). It also retains cold, saving you ice or chiller energy.

If your tub didn't come with a cover, buy one or improvise. A foam insulation board cut to size works surprisingly well. Even a tarp secured with bungee cords is better than nothing.

Once a month, drain the tub completely and do a thorough cleaning. Use a solution of white vinegar and water (1:4 ratio) or a mild non-abrasive cleaner. Scrub all interior surfaces, paying attention to the waterline where biofilm accumulates. Rinse thoroughly — multiple times — before refilling.

For chiller tubs: clean or replace the filter per manufacturer instructions (typically every 1-3 months). Run a line flush product through the plumbing quarterly to prevent biofilm buildup inside the pipes.

Don't use bleach in large amounts — it's harsh on skin and degrades many tub materials. Don't use pool chlorine tablets designed for 10,000+ gallon pools in your 100-gallon tub — the concentration will be way too high. Don't add essential oils or bath products to shared cold plunge water — they clog filters and create biofilm. And don't ignore cloudy water or odd smells. When in doubt, drain and refill. Fresh water is cheap.