The Model Aquatic Health Code: What You Need to Know By Dewey Case
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n 2020, the Council for the Model Aquatic Health Code (CMAHC) began its triennial process of reviewing and evaluating change requests submitted in 2019 for the upcoming edition of the Centers for Disease Control and Prevention’s (CDC’s) Model Aquatic Health Code (MAHC). This was a herculean task as 530 individual change requests were submitted. To make matters more challenging, this review process coincided with the ongoing coronavirus (COVID-19) pandemic, which has impacted people around the world. CMAHC assembled a dedicated group of aquatic professionals, representing such sectors as public health, manufacturing, operations and design. This group gathered to review and debate the 530 change requests prior to October 2020, when all change requests were presented at CMAHC’s triennial Vote on the Code conference. Following the conference, a 30day voting window was opened for CMAHC members to vote on change requests — the results of which will be considered by CMAHC’s Board of Directors with recommendations made to CDC for inclusion in the fourth edition of the MAHC, to be released in summer 2021. This article includes highlights of the 2020 Vote on the Code results. While many change requests are minor — such as clarifying terms or creating more consistency among code sections — others are significant. It is important to note that as of this writing, the process is ongoing.
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The CMAHC Board of Directors will convene in early 2021 to make recommendations for CDC’s review.
The Use of Cyanuric Acid and Isocyanurates Very few things stir up heated discussion like the use of cyanuric acid (CYA). Whether one supports or is against the use of CYA, one thing is true: for many aquatic venues, CYA and the products that contain CYA (isocyanurates) are necessary chemical additions. The addition of this chemical, specifically in outdoor aquatic venues, helps stabilize and shield chlorine from degradation by the sun. Since 2016, a CMAHC committee has studied and debated the use of CYA. As a result of the committee’s research, a novel model was created to identify risk with varying CYA levels. The model was highlighted in an article published in the journal Water (tinyurl.com/y49e3ld4), while its findings were presented at various conferences, including the World
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Aquatic Health Conference. Although significant debate surrounding use of CYAs continues, the research points to a CYA-to-chlorine ratio that does not exceed 45:1 as a best practice. Regarding the CYA change requests for the MAHC, the most significant is the modification to what is considered an imminent health hazard and grounds for immediate closure. This includes when the CYA-tochlorine ratio exceeds 45:1 and when the CYA level exceeds 300 parts per million (ppm), regardless of the ratio.
Harmonization Between the MAHC and ISPSC Since its inception in 2018, a committee formed to address differences in the MAHC and the International Swimming Pool and Spa Code (ISPSC) has identified some discrepancies between the two codes. It is important to note that these are not competing codes. The MAHC is a model code developed by CDC as a resource for authorities having jurisdiction (AHJ) to update their existing codes, or to adopt in whole or in part. Several AHJs have used the MAHC to update their existing codes, while many others use it as a guide for best practices. The ISPSC is part of the family of international codes developed by the International Code Council, which has
