Waterborne Pathogens

Legionella is currently the leading cause of U.S. waterborne disease outbreaks but is still believed to be under-reported. Legionella is different from typical waterborne pathogens in that the route of exposure is inhalation rather than ingestion.

The National Academy of Sciences convened an expert committee to review the state of the science related to the management of Legionella in water systems, formulate recommendations to improve management of Legionella contamination of water systems, and consequently better control Legionnaires’ disease in the United States.  The report was completed in August 2019 and is entitled Management of Legionella in Water Systems. In conjunction with this report, NAS also released interactive science-based guidance for facility managers.

Developing a Water Management Program to Reduce Legionella Growth & Spread in Buildings  features a checklist to help building owners and managers identify where Legionella could grow and spread in a building and ways to reduce the risk of contamination. Information on how events outside of buildings can lead to Legionella growth, such as construction, water main breaks and changes to municipal water quality is also included. AWWA recommends that utilities familiarize themselves with the guide and share it with relevant customers.

Responding to Water Stagnation in Buildings with reduced or No Water Use: A Framework for Building Managers provides a decision-making framework for building managers to design responses to building water system stagnation.

This document provides information to address the immediate need to respond to stagnation. Building managers then can update or create water management programs. Second, this document provides some “how-to” resources for building managers assessing their building plumbing systems after/during stagnation and deciding what level of actions are needed.