Stagnation Increases Health Risks
COVID-19 “stay-at-home” orders have reduced water usage in facilities across the globe as buildings are shutdown or operated with low occupancy. The resulting stagnation in building water system equipment, piping, and fixtures can increase the risk for Legionella and other biofilm associated bacteria to grow, contribute to unsafe levels of lead and copper in potable water systems, and cause other serious problems.
This document was developed to provide building owners and operators with an overview of strategies that can be taken now and when buildings reopen to help address the Legionella risks associated with stagnation. However, due to the complexity of building water systems, the impact of operational and maintenance practices, and the universal nature of Legionella bacteria, no plan, program, or maintenance measures can guarantee the absence of Legionella or transmission of Legionnaires’ disease.
Core Risk Management Strategies
Building water systems can present significant Legionella risks even when fully occupied. Stagnant water increases these risks by causing conditions that favor the growth of biofilms, which are microscopic colonies of surface-attached bacteria directly linked to the growth of Legionella bacteria, and other problems including corrosion and biofouling.
Without flow, the chlorine disinfectant added to the water supplied to a building degrades as it stagnates in potable water systems, causing residuals to drop to ineffective levels. Similarly, the lack of flow in cooling tower systems, decorative fountains, and hot tubs prevents biocide or disinfectant additions from being effective. To compound the problem, stagnation may allow water temperatures to stabilize into the ideal range for Legionella growth (77 to 108°F).
The U.S. Centers for Disease Control (CDC) recommends that building owners follow a recognized process such as ASHRAE 188 to assess Legionella risks and implement a site specific Water Management Program (WMP). Where an active Legionella WMP is in place, the Plan and the Program Team should be referred to for guidance.
The WMP development process tailors maintenance and monitoring protocols to the Legionella risks associated with the building water systems and occupants. For example, procedures appropriate for a commercial office building would not be adequate for a facility with high risk occupants (assisted living, hospital, etc.). Likewise, the startup procedures for a building with an established flushing program during shutdown might be a lot different than the requirements where the building water systems were stagnant. Professional assistance is recommended to evaluate these factors so that appropriate measures can be taken.
With the rapid onset of COVID-19, many impacted buildings will not have a WMP or Program Team in place to provide direction. Regardless, it is important for building owners to understand the basic strategies for addressing water system stagnation so they can be used as appropriate. A site specific legionella WMP should als be developed and implemented when feasible.
Strategies for Potable Water Systems and Equipment
Potable Water Systems
Verify Potable Water Disinfectant Residuals
Domestic Water Heaters
Hot and Cold Domestic Water Storage Tanks
Showerheads and Hoses
Electronic and Manual Faucets
Eye Wash Stations and Emergency Showers
Strategies for Cooling Tower Systems
Strategies for Decorative Fountains
Strategies for Swimming Pools, Hot Tubs, and Whirlpool Spas
Strategies for Misters, Atomizers, and Humidifiers
For additional information and support addressing water stagnation issues in building water systems, supplemental potable water disinfection systems, or any other water management concerns, please contact your local Chem-Aqua Representative or the Chem-Aqua Water Risk Management Services Group by calling 866-209-3373 or emailing email@example.com.
Disclaimer: Due to the universal nature of Legionella bacteria, and its ability to reappear and colonize building water systems, no plan, program, or maintenance measures can guarantee the absence of Legionella or other waterborne pathogens, or eliminate the potential for associated disease. No warranty is made as to the completeness or effectiveness of the risk reduction practices as taught by various published guidelines or governing authorities. Recommendations also do not guarantee that water quality within the assessed systems or procedures will meet governmental or non-governmental standards. Recommendations for Legionella risk reduction may go above and beyond standards or practices intended for optimizing performance or meeting other requirements.
Building Water Systems and Devices Impacted By Stagnation Risks
Core Strategies for Managing
Biofilms and Legionella Risks