Back by Popular Demand: Guide to Minimizing Legionella Risk in Hotels

Back by Popular Demand: Guide to Minimizing Legionella Risk in Hotels

By Hilary Nardone, MPH, Senior Permitting Manager
Certified ASSE 12080 Legionella Water Safety and Management Specialist 

Source: Tom Fisk

The complex piping systems of hotels can be conducive to the growth and spread of Legionella bacteria. Sinks, showerheads, water storage tanks, ice machines, pools, hot tubs, cooling towers, unoccupied rooms and floors, and even a decorative water fountain in the hotel lobby are all places that could harbor Legionella bacteria. The four key factors that affect Legionella bacteria growth in hotels include sediments and biofilms, temperature, oxidant levels, and pluming water stagnation as seen in the graphic below. Luckily, these factors can be managed to minimize the risk of Legionella bacteria growth and amplification in hotel potable water systems.

What is one vital way hotels can mitigate this risk?

The good news is that hotels can reduce growth of Legionella bacteria and other waterborne pathogens by implementing a Water Management Program (WMP) per ASHRAE Standard 188. The Centers for Disease Control and Prevention (CDC) recommends a complete Water Management Program to assess the water systems at the hotel and implement site-specific actions for maximizing water safety. (2) Site-specific actions could include implementing strategies to combat the STOP factors affecting Legionella bacteria growth.

The proactive measure of having a WMP shows that the hotel owners are committed to a safe environment for both their guests and their employees. If a problem in the water piping system arises, this document serves as a clear guide to locate, assess, and respond to the problem quickly. By following this guide, a hotel can decrease the risk of waterborne pathogens, increasing safety and reducing liability.

A comprehensive Water Management Program will touch upon the following general recommendations based on ASHRAE Guideline 12-2023 (1) including but not limited to:

  • If possible, the cold-water system should be stored and distributed below 68°F.
  • If possible, the hot-water system should be stored above 140°F and circulated with a minimum return temperature of 120°F.
  • Periodic removal of shower heads and tap aerators to clean out sediment and scale is recommended. These should be disinfected and reinstalled, or replaced.
  • All water outlets such as faucets, showers and tub spouts should be flushed on a regular basis especially when not in use. Per AWWA/IAPMO, , “flushing outlets once per week may be a starting place of occupied buildings that have infrequently used outlets or some unoccupied spaces… Routine flushing practices can be expanded or reduced based on building occupancy patterns…” (3)


Remember to validate your Water Management Program by testing for Legionella bacteria! Validation is a required component of any WMP. In fact, the CDC recommends sampling for Legionella bacteria to not only validate your WMP, but to also establish a basement measurement for performance indicators and to confirm success or failure of a remedial treatment. (4)

Barclay Water Management has experts ready to help hotels implement Water Management Programs, lessening the risk of guests and employees contracting Legionnaires’ disease. Our services include Legionella bacteria sampling, testing by a CDC ELITE certified laboratory, and result interpretation. Click on the “Contact us!” button to discuss Barclay’s Legionella bacteria control methods.


1.  ASHRAE Guideline 12-2023. Minimizing the Risk of Legionellosis Associated with Building Water Systems. Updated 2023.

2. CDC. Legionella (Legionnaires’ disease and Pontiac Fever): Considerations for Hotel Owners and Managers. CDC. Hotels and Resorts: How to Prevent Legionnaires’ Disease | CDC. Accessed July 26, 2023. Last Reviewed March 25, 2021.

3.  Rhoads WJ, Prévost, M, Pieper KJ, et. al. Responding to Water Stagnation in Buildings with Reduced or No Water Use. AWWA/IAPMO. Published 2020.

4. CDC. Toolkit for Controlling Legionella in Common Sources of Exposure (Legionella Control Toolkit). CDC. Toolkit for Control of Legionella in Common Sources of Exposure | CDC. Accessed July 26, 2023. Updated 2021.

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