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Rationale Behind the MAHC

This page summarizes the data that led to CDC creating the MAHC.

Swimming and other water-related activities are excellent ways to get the physical activity and health benefits needed for a healthy life. We swim hundreds of millions of times in pools, oceans, lakes, rivers, and hot tubs/spas each year 1 and most people have a healthy and safe time enjoying the water. However, the number of outbreaks of recreational water illnesses (RWIs) reported each year has increased significantly over the last few decades 2Drowning and near-drowning 3-6 and pool-related chemical injuries 7-12 continue to occur. This underscores the need to design, construct, operate, manage, and inspect public pools, hot tubs/spas, and water parks to keep swimmers and aquatics staff healthy and safe.

In the United States, there is no federal regulatory agency that holistically regulates or monitors public pools, hot tubs/spas, or waterparks. They are regulated by state or local governments. To assist state and local agencies, CDC has led a national collaborative effort with public health, the aquatics sector, and academic partners from across the United States to develop a national guidance document, called the Model Aquatic Health Code (MAHC), to prevent drowning, injuries, and the spread of germs that cause recreational water illnesses at public swimming pools, hot tubs/spas, and waterparks. The MAHC integrates the latest science and best practices with specific code language and explanatory materials to address the design, construction, operation, and management of public pools, hot tubs/spas, and waterparks.

MAHC Rationale

Rationale for Improving Health and Safety at Public Disinfected Aquatic Facilities

We swim over 300 million times in pools, oceans, lakes, rivers, and hot tubs/spas each year making swimming the fourth most popular sports activity in the United States. It is the most popular sports activity for children and teens. However, over the past few decades, public pools, hot tubs/spas, and waterparks have been associated with significant increases in disease outbreaks and the continued occurrence of drowning and injuries. These health and safety issues include:

  • Drowning. Drowning is a leading cause of unintentional injury-related death for children ages 1–14 years. Non-fatal drowning can cause brain damage resulting in learning disabilities or even permanent loss of basic functioning.
  • Injuries and emergency department (ED) visits. Injuries linked to pool chemicals accounted for 3,000–5,000 ED visits per year. Almost half of the patients are under 18 years of age.
  • Waterborne illness outbreaks. Nearly 500 disease outbreaks linked to pools, hot tubs/spas, and water playgrounds occurred from 2000 to 2014. The leading cause of these outbreaks is Cryptosporidium. This parasite is chlorine tolerant and can cause outbreaks that sicken thousands.
  • Public pool and hot tub/spa closings because of public health hazards. A recent study found that 11.8% (about 1 out of 8) of public pool and 15.1% (about 1 out of 7) of public hot tub/spa inspections resulted in immediate closure because of at least one identified violation that represented a serious threat to public health. Other analyses of inspection data show similar results.
  • Evidence of pool water contamination. Sampling of public pool filter water found 59% (95/161) of samples contained Pseudomonas aeruginosa and 58% (93/161) of samples contained E. coli, an indicator of contamination by feces. Another study of pool filter water found 8.1% (13/161) of samples contained Cryptosporidium, Giardia, or both.

Regulation of Aquatics in the United States

In the United States, there is no federal regulatory authority that holistically regulates or monitors public pools, hot tubs/spas, or waterparks. They are regulated at the state or local level; 68% of local health departments have public pool inspection programs 22. All public pool codes are developed, reviewed, and approved by state and/or local public health officials or legislatures. Consequently, there is no uniform national guidance informing the design, construction, operation, and maintenance of public swimming pools and other disinfected aquatic facilities. As a result, the code requirements for preventing and responding to recreational water illnesses (RWIs), drowning, and injuries can vary significantly among local and state agencies. State and local jurisdictions spend a great deal of time, personnel, and resources creating and updating their individual codes on a periodic basis.

MAHC Vision, Mission, and Anticipated Health Outcomes

The Model Aquatic Health Code’s (MAHC) vision is “Healthy and Safe Aquatic Experiences for Everyone.” The MAHC’s mission is to provide guidance on how state and local officials can transform a typical health department pool program into a data-driven, knowledge-based, risk reduction effort to prevent disease and injuries and promote healthy recreational water experiences. The MAHC provides local and state agencies with uniform guidelines and wording covering design and construction, operation and maintenance, and policies and management of swimming pools and other public disinfected aquatic facilities. The availability of the MAHC provides state and local agencies with the best available guidance for protecting public health so they can use it to create or update their swimming pool codes while conserving valuable time and resources previously used to write or update code language. The guidance is regularly updated using input from the national stakeholder partnership called the Council for the Model Aquatic Health Code (CMAHC) to keep the MAHC up to date and current with the latest advances in the aquatics industry while also responding to public health reports of disease and injury.

Short-term Outcomes: Use of the MAHC should help reduce the risk of diseases and injuries and promote healthy and safe swimming. We anticipate that the practices promoted in the MAHC will initially lead to the following system improvements:

  • Fewer pool and facility closures
  • More-meaningful inspection and tracking/surveillance data
  • An established research agenda to drive future iterations of the MAHC
  • Enhanced collaboration among stakeholders

Long-term Outcomes: By adopting the practices outlined in the MAHC, jurisdictions should also be able to improve the long-term health and safety of aquatic facilities. This should include a reduced risk of the following:

  • Outbreaks of waterborne illnesses
  • Drowning incidents
  • Injuries from pool chemicals and disinfection by-products
  • Swimming-related emergency department visits

CDC is developing systems to track the impact and potential health improvements related to this national public health effort.

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  12. Hlavsa MC, Roberts VA, Kahler AM, Hilborn ED, Mecher TR, Beach MJ, Wade TJ, Yoder JS. Outbreaks of illness associated with recreational water — United States, 2011–2012.  MMWR Morb Mortal Wkly Rep. 2015;64(24);668–72.
  13. Painter JE, Gargano JW, Yoder JS, Collier SA, Hlavsa MC. Evolving epidemiology of reported cryptosporidiosis cases in the United States, 1995–2012. Epidemiol Infect. 2016;144(8):1792-802.
  14. Yoder JS, Beach MJ. Cryptosporidium surveillance and risk factors in the United States. Exp Parasitol. 2010;124:31-9.
  15. CDC. Communitywide cryptosporidiosis outbreak — Utah, 2007. MMWR Morb Mortal Wkly Rep. 2008; 57(36);989–93.
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  17. CDC. Violations identified from routine swimming pool inspections — Selected states and counties, United States, 2008. MMWR Morb Mortal Wkly Rep. 2010;59(19):582-7.
  18. CDC. Surveillance data from public spa inspections — United States, May-September 2002. MMWR Morb Mortal Wkly Rep. 2004;53(25):553-5.
  19. CDC. Microbes in pool filter backwash as evidence of the need for improved swimmer hygiene — metro-Atlanta, Georgia, 2012. MMWR Morb Mortal Wkly Rep. 2013;62(19):385-88.
  20. Shields JM, Gleim ER, Beach MJ. Prevalence of Cryptosporidium spp. and Giardia intestinalis in swimming pools, Atlanta, Georgia. Emerg Infect Dis. 2008;14(6):948-950.
  21. EPA. Beaches. 2014.
  22. National Association of County and City Health Officials (NACCHO). National profile of local health departments. [PDF – 76 pages] 2013. See Page 40.
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