COVID-19 and Building Water Systems

Article – Water Stagnation and Reopening Our Campuses After COVID-19

Article appears in July / August issue of Association of Physical Plant Administrators (APPA) Facilities Manager magazine.

Webinar – Issues, Case Studies and Solutions for Restarting Building Water Systems

30 minute webinar on restarting building water systems after prolonged stagnation. Webinar reviews case studies, public health guidance documents and cost-effective recommendations based on over two decades of experience on what building owners / operators should do when starting building water systems. Targeted to building owners, operators and contractors.

COVID-19 and Legionella – Preparations to consider for Municipal and Building Potable Water Systems

This paper gives direction to building water system owners / operators / contractors and to municipal water providers on steps that can be taken while buildings are idle and municipal mains are operating at very low demand to minimize the risk of Legionella and biofilm growth in building water systems.

Comparison of Public Health Post COVID19 Building Restart Action Items

Many public health building restart guidance documents provide an overview of the issue without any beneficial direction, some including CDC and ICC provide incorrect information. For building owners and contractors interested in doing what is necessary to provide the greatest risk and liability reduction these ‘overviews’ provide limited benefit. The worst guidance documents by far, the CDC and ICC documents listed below, both include a DEADLY wrong temperature range for Legionella growth of 77°F to 108°F. Temperature can be an effective tool for controlling the risk of Legionella growth if water is maintained outside the growth range of 77°F to 122°F, not 77°F to 108°F. In response to comments on this website and the article by Brett Walton listed below some have removed the CDC guidance document from their postings.

This document compares two of the most useful US public health recommendations for post COVID building restarts (Washington State and Ohio) to three of the worst (CDC, EPA, and Pennsylvania). Items are sorted by subject matter for easy understanding.

Documents on this webpage including “COVID-19 and Legionella – Preparations to consider for Municipal and Building Potable Water Systems” and “Chapter 3 Developing a Building Potable Water System Flushing Program” give the most detailed actions that can be taken by building owners, operators and contractors who want to protect their businesses against Legionnaires’ disease risk and liability associated with starting up stagnant potable water systems.

Managing a Legionnaires’ outbreak

Article published in McKnight’s Long-Term Care News (4/10/19) on lessons learned from multi-year CDC failure to resolve Quincy Veterans Home outbreak.

Chapter 3 Developing a Building Potable Water System Flushing Program

This document is Chapter 3 of a book in development. The planned book title is, “Controlling Waterborne Pathogens – Lessons Learned from Two Decades of Field Engineering”. The subject matter is so important today due to the COVID crisis; it is being released in this preprint document. The paper titled, “Considerations for Large Building Water Quality after Extended Shutdown” linked below gives an overview of the issues associated with idle building water system because of COVID-19. This document goes into detail and includes step by step instructions on flushing and disinfection of idle building water systems.


Tim, your document, “Chapter 3 Developing a Building Potable Water System Flushing Program” is great and detailed how-to guidance for flushing and disinfecting stagnant water systems and should be considered by all. Also we’ve followed your guidance in the document “COVID-19 and Legionella – Preparations to consider for Municipal and Building Potable Water Systems” which is more detailed than EPA guidance with regard to contacting municipal suppliers prior to flushing. The municipal providers have been very willing to work with us on buildings with no disinfectant residual at the incoming water supply. In Minneapolis, they wanted to check for themselves and when they verified there was no disinfectant in our supply, they volunteered to flow fire hydrants again (even though they just flowed them three weeks ago). They informed us to watch the incoming residual the following morning and low and behold, it jumped up past 1ppm. Same in Las Vegas, the municipal provider has been very accommodating. We’re on to something that all are very concerned about and have proven the importance of your guidance documents.

Jeff Hardwick
Regional Director, Healthcare | JLL
Enterprise Real Estate Services

Considerations for Large Building Water Quality after Extended Stagnation (COVID-19 response)

I’m proud and excited to be part of the engineering team that developed this paper. The paper raises questions on issues of concern for building owners, public health and municipal water operators. The likelihood for significant illness from building water pathogens is very high when these building are reopened after this unprecedented shutdown. Planning for reopening should take that into consideration and to keep the associated costs and illness as low as possible, building owners should be planning and acting now!

Washington State Dept of Health – COVID-19 Guidance for Legionella and Building Water System Closures

Partly due to comments from this webpage State of Washington Health Department has revised their building water post COVID guidance document.  It is now the best, most comprehensive public health building restart guidance document reviewed to date. 

There are two key items missing from the Washington State document, service line and softener flushing.  Washington State has little to no lead service lines so this item was not added as a focus area.   Hardness of water in Washington state is so low softeners are seldom used so this item was not added.

Ohio Department of Health – Recommendations for Unoccupied to Partially Occupied Buildings for Flushing and Disinfection to Reduce Legionella Growth

Good flushing and disinfection recommendation. Document does recommend up to 200 ppm free chlorine for disinfection, to protect equipment, free chlorine level should not exceed 100 ppm.

ESGLI Guidance for managing Legionella in building water systems during the COVID-19 pandemic

This is an excellent summary by the European Society of Clinical Microbiology and Infectious Diseases. Some notifications on this issue miss some of the key considerations. This document does a good job of highlighting important issues. The guidance details temperatures between 25°C (77°F) and 50°C (122°F) represent a risk for Legionella growth. These are widely accepted ranges of risk.

Contractor Magazine Article highlights newly published UPC Code 2021

New Appendix N of UPC Code 2021 details relationship between temperature ranges associated with Legionella and Scalding risk. These ranges will help building owners during restart avoid temperatures that pose a risk for Legionella.


Problematic Guidance for Building Potable Water Systems Prior to Reopening

‘Deadly’ Consequences if Stagnant Water in Shuttered Buildings Is Not Properly Addressed by Brett Walton

Finally, weeks after CDC published their guidance (document link below) they admit to a serious error that could result in deadly consequences. This excellent reporting by Brett Walton is what pushed CDC into finally changing hot water heater setting recommendations from 120°F to 140°F.

CDC – Guidance for Building Water Systems Ensure the safety of your building water system and devices after a prolonged shutdown

There are multiple issues with this document. The recommendation that hot water heaters be set at least to 120°F was only changed on 5/7 so for weeks many were posting this deadly incorrect information. This was not a confusion in science this temperature is not recommended in any guidance documents including CDC Environmental Infection Control Guideline published in 2003, OSHA guideline published in 1999 and ASHRAE Guideline 12 published in 2000.

Still this guidance lists the growth range for Legionella as (77–108°F, 25–42°C). The range where Legionella grows fastest is between 77°F-108°F, the growth range for Legionella is, as stated in UPC 2021 Appendix N and the ESGLI guidance above, 77°F-122°F.

ICC Code – Guidance for the Disinfection of Building Water Systems using the International Plumbing Code

This document repeats the CDC error above that the growth range for Legionella is (77–108°F, 25–42°C). This error could result in deadly consequences.

This document also recommends disinfecting building water systems by maintaining 200 ppm free chlorine for 3 hours. This level of chlorine is very corrosive and can damage complex equipment and older piping systems. This level is safe in municipal water mains where almost all of the piping is one metallurgy very resistant to corrosion such as cast iron or plastic but in building plumbing systems with many different metallurgies and smaller and complex components this level of chlorine could be very destructive. Check with your equipment manufacturers if this chlorine level will void warranty.


The Quincy Veterans’ Home Multi-Year Legionnaires’ disease outbreak

Did Municipal Water Distribution System Deficiencies Contribute to a Legionnaires’ Disease Outbreak in Quincy, IL?

This peer reviewed paper is the result of two years of investigation and details findings related to the cause of the 2015 Quincy Legionnaires’ disease (LD) outbreak. The paper compares these findings to the circumstances surrounding the 2014 Flint LD outbreak.
To minimize risk for future similar municipal water related outbreaks, municipal plant operators and public health officials should be aware of this papers’ findings and the direct impact significant variations in municipal water corrosion inhibitor and disinfectant residual can have on potential for community wide LD outbreaks as well as outbreaks at buildings housing immunocompromised individuals supplied by this water.

Background Information on US Legionella Policy

Quincy Veterans’ Home Multi-Year Outbreak – A case study in failed US Policy

Managing a Legionnaires’ outbreak

Article published in McKnight’s Long-Term Care News (4/10/19) on lessons learned from multi-year CDC failure to resolve Quincy Veterans Home outbreak.

Whitewash? Quincy Veterans’ Legionnaires’ disease report by Illinois Auditor ignores Expert reports’ findings and recommendations

LRM IDPH Public Comments On Illinois Plumbing Code By Tim Keane Legionella Risk Management 12 28 18


Supporting Documents

CDC Epi-Aid Report – Quincy 8/31/2015

CDC Epi-Aid Report – Quincy 8/8/2016

CDC Epi-Aid Report – Quincy 12/4/2017

CDC Epi-Aid Report – Quincy 2/4/2018

Restaurant outbreak of Legionnaires’ disease associated with a decorative fountain: an environmental and case-control study

CDC Sampling Procedure and Potential Sampling Sites.  Protocol for collecting environmental samples for Legionella culture during a cluster or outbreak investigation or when cases of disease may be associated with a facility.

Tim Keane Presentation to National Academy of Sciences, Medicine and Engineering titled, “Successes and failures in cost effective public health policy related to control of Legionella in building water systems”

Janet Stout Presentation at Emory University portion on sampling protocol of 1st draw vs 2 minute flush “There are people out there doing this intentionally to get negative results”   

Janet Stout Presentation at Emory University entire presentation

Preventing Waterborne Pathogen Transmission by Kelly Pyrek ICT March 2019

CDC Guidelines for Environmental Infection Control in Health-Care Facilities 2003 (title and  Legionella pages 54 – 56)

Illinois Auditor General Report Legionnaires’ Disease at the Quincy Veterans Home  March 2019