Frequently Asked Questions About the MAHC

The MAHC

• Is guidance that state and local governments and the aquatics sector can use to prevent drowning, injuries, and the spread of germs that cause recreational water–associated illnesses at public swimming pools and hot tubs/spas.
• Integrates the latest knowledge based on science and best practices with specific code language and explanatory materials.

Covers the design, construction, operation, and maintenance of swimming pools, hot tubs, splash pads, and other public disinfected aquatic facilities.

People in the United States swim more than 300 million times in pools and other bodies of water each year, making swimming one of the most popular sports activities in the United States and the most popular sports activity among children and teens ¹. However, over the past few decades, public aquatic venues have been associated with significant increases in the number of disease outbreaks reported for each year and the continued occurrence of drowning and injuries. These illnesses and injuries can be prevented by proper operation and management.

More information about Healthy Swimming

The MAHC is needed to help prevent outbreaks, drowning, and injuries and to reduce the need for public pools and hot tubs/spas to be closed immediately for serious health and safety hazards. Many of these problems can be prevented by proper operation and management. However, in the United States, there is no federal agency that regulates aquatic facilities, so public pools and hot tubs/spas are typically regulated by state or local governments. In fact, 68% of local health departments inspect public pools ². States and local communities spend a great deal of time, personnel, and resources creating and updating their individual codes on a regular basis. The MAHC is a tool to help state and local governments and the aquatics sector reduce risk illness and injuries in their communities while saving time, resources, and staying up to date with the latest science.

The MAHC provides sample code language and explanatory text covering design, construction, operation, maintenance, and management standards. Most of the guidelines for design and construction pertain only to new construction and substantial alteration. This guidance language can be used in whole or key components can be used individually. The MAHC Code wording is accompanied by an annex summarizing the scientific evidence base, research, and other materials used to inform the MAHC guidance.

View the current MAHC Code and Annex

Use of the MAHC is expected to help reduce the risk of illness and injuries and promote healthy and safe swimming.

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:

• Reduced need for immediate closures for serious health and safety hazards
• Uniform inspection or 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 at aquatic facilities. This should include a reduced risk of the following:

• Outbreaks of waterborne illnesses
• Drowning
• Injuries from pool chemicals and other causes
• Swimming-related emergency department visits

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

Creating the MAHC was a collaborative effort led by the Centers for Disease Control and Prevention and more than 140 volunteers from across the United States with expertise in public health or aquatics. These experts included federal, state and local public health officials; researchers; and representatives of the aquatics industry, certification organizations, and not-for-profit aquatic associations.

Learn more about the creation of the MAHC.

The MAHC code language is accompanied by an annex that provides more information about the content of the MAHC code and the scientific rationale for the guidance in the MAHC.

The annex:

• Gives explanations, scientific data, and references to support why specific recommendations were made;
• Discusses the rationale for making decisions on best practices when scientific data are not available;
• Explains why other scientific data might not have been selected (for example, inconsistencies in data);
• Highlights areas where additional research might be needed;
• Provides additional information, including summaries of scientific studies, charts, graphs, or other reference materials.

Cryptosporidium is a microscopic, extremely chlorine-tolerant parasite that causes the diarrheal disease cryptosporidiosis. Both the parasite and the disease are commonly known as “Crypto.” Outbreak investigations routinely show that many people continue to swim despite having a diarrheal illness. During 2000-2014, Crypto caused about 500 outbreaks associated with recreational water, resulting in over 27,000 cases of illness ³. As an extremely chlorine-tolerant parasite, Crypto can survive for days even in a well-chlorinated pool. The MAHC can help prevent Crypto outbreaks by highlighting evidence-based practices that can reduce the risk of spread of germs that cause recreational water–associated illness. The MAHC recommends additional, or secondary, disinfection safeguards such as ultraviolet light or ozone, which kills Crypto, particularly when there is increased risk of germ contamination (e.g., wading pools and splash pads).

The MAHC is a free, open-access, all-inclusive resource developed to help states and local communities ensure that their aquatic codes are based on the latest and most scientifically sound data available. The MAHC complements building-specific codes, such as the Uniform Swimming Pool, Spa and Hot Tub Code (USPSHTC) developed by the International Association of Plumbing and Mechanical Officials (IAPMO) and the International Swimming Pool and Spa Code (ISPSC) developed by the International Code Council (ICC).

To ensure that the various pool codes are complementary, CDC has paid careful attention to avoid conflicts between the MAHC and building codes. The MAHC primarily addresses issues for which environmental public health officials have principal regulatory responsibility, including aspects of design and construction that impact public health and all aspects of operations. Codes like the USPSHTC and the ISPSC are intended primarily to address issues over which building code officials have principal regulatory responsibility, including most structural, mechanical, and electrical components.

In addition, the MAHC primarily addresses public pools and hot tubs/spas, whereas other codes might apply to residential pools and hot tubs/spas.

The Virginia Graeme Baker Pool and Spa Safety Act (VGB) is a federal law passed in 2008 that requires public pools and hot tubs/spas to use unblockable drain covers or other specified devices or systems designed to prevent suction entrapment. Entrapment can occur when a body part or an object worn by the swimmer, such as jewelry, becomes entangled or stuck in the suction outlet cover, or when a body part forms a seal and suctions the swimmer to the outlet cover. The implementation of VGB is overseen by the Consumer Product Safety Commission.

There are several differences between the MAHC and VGB. The MAHC addresses a broad and complete range of public health concerns, including outbreaks, drowning, injuries, through design, construction, operation, maintenance, and management. VGB relates to only drain covers. While the VGB is a federal law requiring compliance, the MAHC is not a federal law and carries no regulatory authority unless adopted, in whole or part, by a state or local community. Rather, the MAHC is a resource that state and local governments can use to update their own codes. The MAHC was created through a collaborative effort among public health and the aquatics sector, with opportunities for public review and comments. VGB targeted all pools; the MAHC design and construction elements pertain primarily to only new construction or substantial alteration (and only in those jurisdictions that adopt the MAHC).

The MAHC is not a federal law, so it will primarily affect the aquatics sector operating in states and local communities that choose to adopt all or parts of the MAHC. For larger aquatics organizations in multiple states or local communities, the MAHC could lead to more consistent design, construction, operation, maintenance, and management guidance for public pools and hot tubs/spas. In addition, expanded MAHC adoption would allow multi-state organizations to have a single, robust risk reduction effort that applies to locations across the United States.

By incorporating the MAHC guidance, aquatics facilities can reduce the risk of outbreaks of waterborne disease, drowning, and injuries at their facilities. It is important to note that many MAHC provisions, particularly those related to design and construction, pertain primarily to only new construction or substantial alteration and will not require retrofitting of existing pools.

The aquatics sector has been heavily involved in the creation of the MAHC alongside public health experts. This helps ensure that the guidance proposed by the MAHC drives meaningful change while reflecting practical realities. CDC hopes that the design, construction, operation, maintenance, and management of aquatic facilities become increasingly science-based through gradual changes that allow all parties to prepare. CDC shares the aquatics sector’s goal of making swimming healthy and safe.

The MAHC is intended to provide optional and voluntary language to make the construction and operation of pools safer and healthier. States and local communities that choose to adopt the MAHC will likely affect pool construction and operation by incorporating science-based practices into pool operation.

MAHC provisions relating to design and construction will pertain primarily to the construction of new or substantially altered aquatic facilities and will not require retrofitting of existing aquatic facilities. Over time, adoption of the MAHC guidance could drive greater consistency in aquatic facility construction and operation requirements.

In the United States, there is no federal regulatory authority responsible for design, construction, operation, maintenance, and management of public pools and hot tubs/spas. State or local officials develop, review, and approve all pool codes. These codes are implemented by state or local public health officials and, in some cases, building code officials; 68% of local health departments have a pool inspection program.

As a federal agency, CDC tracks illnesses and injuries associated with recreational water nationally through reports it receives from state and local partners. When state and local public health officials detect an outbreak associated with treated recreational water, they might ask CDC to investigate or help control the outbreak. Data collected during outbreak investigations and through research are then used to inform CDC prevention (e.g., health communications and policy) recommendations to state and local officials. As part of the response to prevent future outbreaks, drowning, and injuries, CDC has been committed to aquatic health and safety since the 1950s when it issued its first of a series of aquatic health and safety guidance documents to state and local public health agencies and the aquatics sector. CDC has continued to issue assistance and guidance since that time culminating in the creation of CDC’s Healthy Swimming Program in 2001.

Each jurisdiction’s aquatic health and safety code is different and will have to be evaluated by stakeholders in that jurisdiction. The MAHC has attempted to identify keys areas for improvement based on scientific data and current best practices, learning lessons from outbreaks, and other data sources.

For example, hygiene is an important issue that is linked to the spread of germs in pools and hot tubs/spas. The MAHC is intended to help improve swimmer hygiene to reduce the risk of the spread germs associated with poor swimmer hygiene. Thus, the MAHC has recommendations for new or substantially altered construction that include the following:

• Maximum distances for hygiene facilities from aquatic facilities
• Criteria for diaper-changing stations
• Implementation of rinse showers in addition to cleansing showers

• The MAHC is a guidance document and not a federal law and is only enforceable once adopted by a particular state or local community. The MAHC provides guidance on minimum standards for the design, construction, operation, maintenance, and management of public pools and hot tubs/spas needed to protect public health and safety.
• State or local stakeholders should evaluate the current laws and practical considerations to determine the most appropriate use of the MAHC. Stakeholders might choose not to adopt the MAHC at all or might choose to adopt or revise all or parts of it to meet their needs.

• The MAHC addresses a wide variety of aspects of aquatic health and safety, including operator training, risk management, ventilation and air quality, recirculation and filtration, facility design, and others.
• Stakeholders should evaluate current laws and practical considerations to determine the most appropriate use of the MAHC. Stakeholders might choose not to adopt the MAHC at all or might choose to adopt or revise key parts of the MAHC to meet their needs.

• Having few outbreaks, drownings, and injuries does not mean prevention recreational water–associated illness and injury is optimal. States and local communities should also consider the recent increase in outbreaks of Cryptosporidium, which is not effectively controlled by chlorine, as they review their aquatic health and safety codes.
• The MAHC is based on the best scientific data available for protection of public health. These guidelines are based on the principle of reasonable risk reduction, meaning that they are intended to minimize opportunities for recreational water–associated illness and injury. As is the case with many public health prevention efforts, the value is often more easily understood after a tragedy occurs, such as a drowning, injury, or outbreak. By incorporating evidence-based practices based on the science, states and local communities reduce the likelihood of these events occurring.

For more information, please contact us at MAHC@cdc.gov.