Supplement Feature - February 2021
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Just Keep Swimming

The 2021 Aquatic Trends Report

By Emily Tipping

Tracking Usage of the MAHC

Established by the U.S. Centers for Disease Control & Prevention (CDC), the Model Aquatic Health Code (MAHC) brings together the most up-to-date science and best practices with the goal of helping state and local government officials develop and update their pool codes. Historically developed at the local and state level, such codes govern pool operations, including how and how often water is tested, how aquatic facilities are built, how chemicals should be used to keep water safe and free from disease and more. The MAHC aims to create a more standardized set of guidance to establish rules and regulations for aquatic facilities that are based on industry consensus around best practices.

The MAHC was first released in the summer of 2014, but it is a fluid code, meant to be updated regularly as new information and input is made available. The third edition of the code was published in 2018, and the fourth edition is anticipated to be released for the summer 2021 swim season, according to the Council for the MAHC.

The code is not a federal law, which means government agencies can choose whether to adopt it at all, whether to use all of the MAHC or just part of it, or whether to modify all or part of it to fit their needs.

Nearly six in 10 (57.3%) respondents said they are familiar with the MAHC, representing virtually no change from last year's survey. Some 19.8% said they are very familiar with the MAHC, and 37.5% are somewhat familiar. (See Figure 25.)

To ensure the MAHC is regularly updated, a nonprofit organization, the Council for the Model Aquatic Health Code (CMAHC) was created in 2013. The council serves as a clearinghouse for input and advice on improvements to the MAHC. CMAHC members can take part in the process of updating the MAHC and have their input heard by the CDC as it revises and releases the next edition. (To learn more about participating in the CMAHC, visit

While a majority of respondents to the Aquatic Trends survey said they did not participate at all in the CMAHC, some 7.9% had some involvement, and 1.4% are on the committee itself.

We also asked respondents whether the regulatory agency that governs their facilities has adopted the MAHC, either fully or partially. The largest number of these respondents—44.4%—were not sure, down from 46.3% last year. One-third (33.8%) said their regulatory agency had not adopted the MAHC. Some 4.9% said the MAHC had been fully implemented by their regulatory agency, and 16.9% said their agency had adopted portions of the code. (See Figure 26.)