Cold Plunge Guidance Calls for 3 ppm Chlorine, 30-Minute Turnover and a 5-Minute Sign

US health departments now have a template for cold plunge plan review and inspection. The Council for the Model Aquatic Health Code, which collects, assesses and relays recommendations on the CDC’s Model Aquatic Health Code for public pools, released cold-water venue guidance in July. It covers cold plunges, ice baths, cold-soak tubs and drain-and-fill pools, from built-in vessels to single-user plug-and-play units.

The guidance “does not create regulatory requirements.” Your health department decides what applies. It was written for health agencies, operators, designers and builders, and the committee was chaired by Sarah Cheshire of Utah’s health department. It included the CDC, public health members from Wisconsin, North Carolina, Canada and Queensland, Australia, and industry members including Life Time and IAPMO.

Cold water is harder to keep clean

The guidance classes cold-water venues as high-risk under the model code because chlorine and bromine work more slowly in cold water and organic loads run higher. Hence the 3.0 ppm floor, continuous automated dosing, and the push toward UV or ozone.

Two equipment calls stand out:

• Test kits. Most poolside kits read inaccurately at low temperatures. Use kits designed for cold water, or warm the sample before testing, and keep the records.
• Salt systems. In-line electrolytic chlorine or bromine generators are “generally not recommended,” because, on limited evidence, they may make disinfectant more slowly in cold water and raise total dissolved solids. A health department may consider approving one case by case if the manufacturer documents low-temperature performance. Batch or side-stream generators don’t raise the same concern.

Small or busy venues may need more frequent water replacement than a typical pool. The guidance also calls for monitoring combined chlorine and keeping a documented cleaning schedule against biofilm.

Single-user tubs: drain between bathers, or treat the water continuously

The guidance singles out plug-and-play tubs, noting that many were built for residential use and “may not meet MAHC design and construction standards without modification.” It gives operators two paths:

• No continuous recirculation, filtration and automated chemical control: drain, clean, disinfect and refill the tub between bathers.
• Shared water: continuous treatment that meets the model code, plus replacement water of at least 4 gallons per bather per day, and often more in small tubs.

It tells inspectors to require plan review for single-bather systems, to check that drain-and-refill units actually follow the process, and to judge them on performance rather than on whether they look like a traditional pool. New York’s spa-pool definition already turns on the same drain-or-treat line, as our look at a cold plunge’s three legal identities found.

What goes in the plan review packet

Beyond the model code’s usual items, the guidance asks for:

• the target operating temperature
• the circulation and treatment system design
• peak occupancy, figured at 10 square feet per bather
• condensation control for indoor rooms
• documentation that chillers, controllers, filters and pumps hold up to low temperatures and repeated disinfectant exposure

The signs

The guidance recommends posting these statements where bathers decide whether to get in:

• “Bathers should not spend more than 5 minutes in the cold-water venue in any one session.”
• “Bathers should not use the cold-water venue alone.”
• “Children aged 14 years and younger are prohibited from bathing in a cold-water venue, unless under the direct supervision of a licensed medical professional.”
• “Due to the risk of cold shock from total or partial immersion in cold water, any bather should consult a physician before using the cold-water venue.”
• “Elderly persons, pregnant women, persons using prescription medications, and those suffering from heart disease, diabetes, or high blood pressure should consult a physician before using the cold-water venue.”
• “Individuals under the influence of alcohol or other impairing chemical substances should not use the cold-water venue.”
• “Persons suffering from a communicable disease transmissible via water may not use the cold-water venue.”

It also recommends a sign on the effects of sudden cold exposure and one prohibiting running and horseplay.

What it doesn’t settle

The guidance doesn’t apply to private residential use, natural bodies of water, or temporary or inflatable portable systems unless a health department otherwise regulates them. It doesn’t override state rules either. Washington already treats commercial plunges as spa pools, as covered in the cold plunge code fight, and California’s bill to carve out single-user tubs stalled in the Assembly in May.