Now Available: 2023 Model Aquatic Health Code (4th Edition)

On February 1, 2023, the Centers for Disease Control and Prevention (CDC) announced the release of the 2023 MAHC (4th edition), which includes two documents: 

  • Code: model code guidance that aims to prevent illness and injury associated with public aquatic venues through venue design, construction, operation, and management. 
  • Annex: the scientific and best practices rationale on which the model code language is based. 

U.S. local, state, territorial, and tribal officials can voluntarily use the MAHC to help reduce risk of pathogen transmission and injuries (including drowning) associated with public pools, hot tubs, or splash pads.

What's new?

The 2023 MAHC includes important updates to help prevent:
  1. Pathogen transmission: 
    • making cyanuric acid to DPD (N,N Diethyl-1,4 phenylenediamine sulfate)-free chlorine concentration ratio greater than 45:1 a closure item. 
    • decreasing minimum pH to 7.0.
  2. Drowning: establishing a maximum vertical clearance at the bottom of an aquatic venue or facility enclosure (no more than 2 inches above non-solid grade and no more than 4 inches above solid grade). 
  3. Spinal cord injuries: increasing the minimum water depth to 6 feet for new construction of starting platforms. 

Website updates in progress:

CDC is in process of updating its MAHC website and will post the 2023 MAHC there over the next few weeks. It will also be updated in "The MAHC" section of on CMAHC's website soon. In the meantime, you can download the 2023 MAHC (4th edition) here:

2023 MAHC (4th edition): 

2023-MAHC-508.pdf 3.5 MB

2023 MAHC (4th edition) Annex:
2023_MAHC_ANNEX-508.pdf 4.42 MB

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