Cold plunges are becoming increasingly popular at fitness centers, hotels, spas, and other commercial aquatic facilities. However, maintaining a shared cold plunge involves more than simply lowering the water temperature.
The Council for the Model Aquatic Health Code (CMAHC) has released new guidance addressing the design, operation, sanitation, and safety of public cold-water venues.
We’ve summarized the most important recommendations for commercial pool operators, facility managers, and aquatic professionals. Find a link to the complete document below.
1. Design and Construction
- Water temperature: The guidance defines cold-water venues as aquatic facilities operating below 70°F, generally intended for immersion periods of five minutes or less.
- Bather capacity: Designers should establish a maximum occupancy based on the vessel’s intended use. The guidance recommends a design assumption of 10 square feet per bather.
- Equipment compatibility: Chillers, pumps, filters, chemical controllers, piping, and pool finishes should be suitable for continuous cold-water operation.
- Condensation control: Indoor facilities should address moisture accumulation caused by cold water and warmer surrounding air, which can contribute to structural damage and microbial growth.
- Regulatory approval: New installations and conversions should be reviewed with the local authority having jurisdiction to determine applicable permitting and operating requirements.
2. Circulation and Filtration
- Continuous circulation: Shared cold-water venues should maintain continuous water circulation and effective filtration.
- Turnover rates: The guidance generally recommends spa-like turnover rates of 30 minutes or less.
- Surface skimming: Effective skimming is important for removing contaminants introduced by bathers.
- Certified filtration: Filters should be appropriately sized and certified to recognized standards, such as NSF/ANSI/CAN 50.
- Flow verification: Operators should regularly verify circulation performance, maintain filters, and promptly address interruptions in water treatment.
3. Water Sanitation and Disinfection
- Chlorine: The guidance recommends maintaining free chlorine at or above 3.0 ppm, subject to applicable limits.
- Bromine: Bromine is another acceptable sanitizer, with a recommended minimum residual of 4.0 ppm.
- Cyanuric acid: The use of chlorine stabilizers containing cyanuric acid is not recommended for cold-water venues.
- Automated chemical control: Automated dosing systems should include interlocks that prevent chemical feeding during low-flow or no-flow conditions.
- Supplemental disinfection: UV, ozone, and advanced oxidation systems should be strongly considered. In-line electrolytic sanitizer generators also warrant caution because some systems perform poorly at low temperatures.
4. Water Quality Testing and Maintenance
- Cold-water testing: Standard pool test kits may not perform accurately at very low temperatures. Operators should use suitable testing methods or warm samples as directed before testing.
- Water chemistry: Sanitizer residuals, pH, combined chlorine, and water clarity must be regularly monitored and maintained within appropriate operating limits.
- Cleaning procedures: Documented cleaning schedules help control biofilm, organic contamination, and deterioration of pool surfaces.
- Water replacement: Smaller or heavily used cold plunges may require more frequent water replacement than conventional swimming pools.
- Indoor air quality: Proper ventilation is necessary to control humidity, moisture, and airborne chloramines in indoor facilities.
5. Bather Safety and Facility Operations
- Cold shock: Sudden immersion can cause involuntary gasping, rapid breathing, increased heart rate, and elevated blood pressure, creating serious safety risks.
- Immersion limits: The guidance recommends that bathers spend no more than five minutes in the cold water during a single session.
- Health precautions: Warning signs should identify risks for individuals with cardiovascular conditions and other medical concerns. Bathers should not use cold plunges alone.
- Safe entry and exit: Facilities should provide appropriate steps, handholds, slip-resistant surfaces, visible thermometers, and clocks to help bathers monitor immersion time.
- Staff training: Operators should establish written procedures for water treatment, equipment maintenance, emergency response, and bather safety. An attendant trained in CPR, first aid, and safe extraction is recommended on-site during operating hours.
Download the Complete Cold-Water Venue Guidance
These recommendations provide a starting point for operators considering or managing cold-water facilities. The complete CMAHC document contains additional guidance for public health officials, designers, facility owners, and operators.
Download the Official MAHC Cold-Water Venue Guidance (Free PDF)
Important: This document provides voluntary guidance and does not automatically establish regulatory requirements. Always consult your state or local health department regarding requirements applicable to your facility.
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