The MAHC Current Edition
This page includes the current, or latest, edition of the MAHC code and annex.
All previous MAHC editions are superseded by the latest and most current edition of the MAHC and are archived on the Previous MAHC Editions page. All of the information pertaining to development of the MAHC, including all of the drafts and modules released during the development of the 2014 MAHC (1st Edition), can be found on the Creating the MAHC page.
2018 MAHC (3rd Edition)
To use a full database-driven search function for all editions of the MAHC, including the ability to pull the MAHC code and annex up at the same time, visit the CMAHC’s Search the MAHC page.
A Microsoft Word version of the MAHC code and/or annex can be provided to potential users on request by emailing MAHC@cdc.gov.
See 2018 MAHC (3rd Edition) errata below.
Specific public health issues addressed in the MAHC are often spread across multiple chapters. Mini-MAHCs are intended to make the MAHC more accessible by aggregating the code and annex language into more concise documents. This will help environmental health practitioners and pool operators quickly find relevant MAHC guidelines and rationale to solve specific public health issues and improve patron and staff health and safety. All mini-MAHCs reference content from the 2018 MAHC (3rd Edition).
Reducing the Spread of Cryptosporidium
This Mini-MAHC Code focuses on reducing the spread of Cryptosporidium (Crypto). The language presented will help decrease the public health impact of contamination through: inactivation of oocysts by secondary U.V. or ozone disinfection systems, inspection of systems, and remediation after diarrheal fecal incidents to prevent the spread of Crypto associated with swallowing contaminated water.
Errata: 2018 MAHC (3rd Edition)
To avoid version control issues for the 2018 MAHC, CDC will post noted errors in this space with the correction in bold.
- 220.127.116.11.2: pg 5, bullet. MAHC Code
- 4.6.11: Adds acoustic criteria to natatorium design to reduce noise levels. (4.6.11)
- 18.104.22.168, pg 91. MAHC Code
- 22.214.171.124: pg 137. MAHC Code
- Drainage and Replacement. Spas shall be drained, cleaned, scrubbed, and water replaced as calculated in MAHC 126.96.36.199.1.
- Section 8. Resources: Reference 387 on pg 226 and 246 of MAHC Annex
Key Changes Found in the 2018 MAHC (3rd Edition)
The MAHC is updated every 3 years and includes opportunities to submit requested changes through the Council for the Model Aquatic Health Code (CMAHC). For the 2018 edition, 179 change requests were submitted for CMAHC member voting at the 2017 CMAHC conference. Of these, 122 (68%) change requests were passed by CMAHC vote. CDC reviewed the change requests and accepted 115 (94%) of the 122 MAHC change requests that the CMAHC membership.
The 2018 MAHC includes structural changes, clarifying edits, and new or revised recommendations in the areas of disinfection and water quality; lifeguarding and bather supervision; and risk management and safety.
A track changes version of the MAHC 3rd Edition Code and Annex can be used to see what changes were made to the 2016 MAHC (2nd Edition) to create the 2018 MAHC (3rd Edition).
- 2018 MAHC Code (3rd Edition) – 07/18/2018 (for print only) [PDF – 197 pages] — Track Changes Version
- 2018 MAHC Annex (3rd Edition) – 07/18/2018 (for print only) [PDF – 300 pages] — Track Changes Version
Correspondence between the CMAHC and CDC on suggested changes to the MAHC is posted below.
- CMAHC voting results letter regarding change requests for 2018 MAHC (3rd Edition) – 01/19/2018 (for print only) [PDF – 5 pages]
Overview of Key Changes
Note: This short list is a high-level summary only. Please consult the Track Changes version of the 2018 MAHC to review all changes. A detailed list of changes and their section location is in Section 1.6 – Modifications and Improvements in the 2018 MAHC.
- Color Scheme
- The Code and Annex covers are completely different colors so they can be readily differentiated.
- All pages have a header with edition number for easy reference.
- Individual sections have edition number and date like main cover to avoid confusion.
- Code –Annex linkage
- All code sections with accompanying annex wording have a superscript “A” next to the MAHC section number to make it easier to know when to refer to the annex for further information.
- The glossary sections for code and annex have been separated so it is clear which acronyms, initialisms, and terms are code and annex specific.
- Added a new section (3.3) in the code and annex to list what codes, standards and laws are specifically referenced in the code section vs. citation in the annex.
- Annex Resource section 7.1 has been edited to include only guidelines cited. All cited codes, standards, and laws have been moved to the new Glossary section 3.3.
- Extensive small edits and clarifications of language.
Disinfection and Water Quality
- New: Establishes guidance for responding to Legionella (188.8.131.52)
- New: Establishes guidance for floatation tank regulation. (4.12.10/5.12.10)
- New: Outlines performance criteria for disinfectant feeders with sizing dependent on stated chlorine demand factors. (184.108.40.206.2.2-0003/220.127.116.11.2.3/18.104.22.168.1.5)
- New: Specifies that numerous pool chemicals (stabilizers, pool-grade salt, clarifiers, flocculants, defoamers, and pH adjustment chemicals) must meet either NSF/ANSI Standard 50 or NSF/ANSI Standard 60, and/or have a U.S. EPA FIFRA registration. (5.7.3)
- Strengthened: Defines additional requirements to improve chemical control and feed system interlocks and no/low flow deactivation. (22.214.171.124.1.3/126.96.36.199.4.1.1/188.8.131.52.1.1.1/184.108.40.206.2.6/220.127.116.11.1.2/18.104.22.168.1.4.1/4.1.6)
- Flexibility: Lowers secondary disinfection performance to a minimum 2-log reduction for all venues except interactive water play aquatic venues. (22.214.171.124.2)
- Flexibility: Raises calcium hardness maximum levels to 2500ppm. (126.96.36.199.3)
Lifeguarding and Bather Supervision
- New: Requires lifeguards if alcohol served at aquatic venue. (188.8.131.52-0001)
- New: Requires lifeguard personal protective equipment to be on person or rescue tube. (184.108.40.206.9)
- Strengthened: Clarifies glare assessment for lifeguard positions. (220.127.116.11.1.1)
Risk Management and Safety
- New: Adds acoustic criteria to natatorium design to reduce noise levels. (4.6.11)
- New: Adds certification for pool lifts. (5.10.2)
- New: Makes stair tread dimensions uniform. (5.4.5)
- Flexibility: Improves enclosure requirement language and delineates exceptions. (18.104.22.168.1.1/22.214.171.124.1.2/126.96.36.199.7-0002)
- Flexibility: Clarifies requirements for closure and reopening. (188.8.131.52.1/184.108.40.206.2/220.127.116.11.3)
- Flexibility: Clarifies handhold wording for lazy rivers. (18.104.22.168.2-0001/22.214.171.124.2-0002)
Overview of Change Requests Not Accepted by CDC
CDC did not accept seven of the change requests (CRs) submitted by the Council for the Model Aquatic Health Code. These change requests and the reasons for CDC’s rejection are outlined below.
- CR 126.96.36.199.2.1.4: Permissive use of safety vacuum release systems (SVRS)
Rationale: The Virginia Graeme Baker Act requires SVRS when there is only a single main drain. However, the MAHC requires a minimum of two main drains. Therefore, CDC found there should not be a need for a requirement addressing SVRS devices in this section. Additionally, the American National Standard for Suction Entrapment Avoidance In Swimming Pools, Wading Pools, Spas, Hot Tubs, and Catch Basins [ANSI/APSP/ICC-7 (2013)] cautions about incompatible configurations of SVRS. The suggested language that SVRS “…may be installed…” is permissive and could be interpreted as the MAHC giving permission for installation in a potentially incompatible configuration. Permissive language is not acceptable for MAHC code language.
- CR 188.8.131.52.2-0002: Adding log removal credit for secondary disinfection systems
Rationale: The change request did not include needed details regarding “log removal credits” or a filtration system validation protocol for Cryptosporidium log reduction.
- CR 184.108.40.206.3.3: Changes in Ultraviolet (UV) system installation
Rationale: The change request alters the installation requirements while not addressing all of the elements necessary for proper design and operation of the system and could significantly increase the required capacity and associated cost of the UV unit. CDC suggests this change be considered as part of a comprehensive evaluation of interactive water play venue design requirements. CDC encourages the CMAHC to convene an interactive water play venue design Ad Hoc Committee to further discuss this issue and re-submit a change request, as needed, after the discussion.
- CR 220.127.116.11.3: Requiring flow meters at slides
Rationale: Although the use of flow measuring devices is important, the design and operation of Water-Related Amusement Rides is already covered in the internationally recognized ASTM Standard Practice for Classification, Design, Manufacture, Construction, and Operation of Water Slide Systems [F2376-17a (2017)]. CDC believes this is outside the scope of the MAHC and encourages work with ASTM to develop appropriate safety protections that can be included in the existing ASTM standard and referred to in the MAHC. Wording is being developed to clarify the MAHC scope for future CR submissions.
- CR 18.104.22.168.4: Requiring scales at slides
Rationale: The design and operation of Water-Related Amusement Rides is already covered in the internationally recognized ASTM Standard Practice for Classification, Design, Manufacture, Construction, and Operation of Water Slide Systems [F2376-17a (2017)]. CDC believes this is outside the scope of the MAHC and encourages work with ASTM to develop appropriate safety protections that can be included in the existing ASTM standard and referred to in the MAHC. Wording is being developed to clarify the MAHC scope for future CR submissions.
- CRs 22.214.171.124.1 and 126.96.36.199.2: Changing “must” to “shall”
Rationale: In these two sections, use of “must” is appropriate as the word is used in a list versus in regulatory or enforcement language where shall would be chosen.
- Page last reviewed: November 19, 2018
- Page last updated: November 19, 2018
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