ASHRAE 188-2018 Update – Legionellosis: Risk Management for Building Water Systems

Written by: Hilary Nardone, Lead Environmental Group Manager

In August 2018, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) updated its Standard 188 Legionellosis: Risk Management for Building Water Systems that was originally implemented in 2015. The ANSI/ASHRAE Standard 188-2018 standardizes water management programs for facility water systems to mitigate the risk of Legionella bacteria. This updated standard supersedes ANSI/ASHRAE 188-2015.

This Standard is continuously maintained by a Standing Standard Project Committee (SSPC) for which the Standards Committee has established a documented program for regular publication for addenda or revisions, including procedures for timely, documented, consensus action on requests for change to any part of the Standard.


ASHRAE Standard 188 establishes minimum legionellosis risk management requirements pertaining to:

  • Building water systems including design, construction, commissioning, operation, maintenance, repair, replacement and expansion of new and existing buildings and their associated (potable and non-potable) water systems and components.
  • Human-occupied commercial, institutional, multi-unit residential, and industrial buildings. This Standard does not include single-family residential buildings.
  • Owners and managers of human-occupied buildings, excluding single-family residential buildings. This Standard is also intended for those involved in the design, construction, installation, commissioning, operation, maintenance, and service of centralized building water systems and components.

Update Highlights:

The changes to ASHRAE Standard 188 do not implement new requirements. Instead, the revised Standard improves usability.

  • Includes clarification of compliance requirements
  • Comprehensive update to enforceable, code-intended language to facilitate the adoption of the standard for code and regulatory purposes
  • Addition of informative annexes

Rest Assured:

All of the Water Management Programs created by Barclay Water Management, Inc.’s Environmental Group remain in compliance with the ANSI/ASHRAE Standard 188-2018!

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