The warehouse reopened smoothly when COVID restrictions eased: picking equipment functioned at speed, loading dock mechanisms obeyed switches, HVAC systems whooshed to life as expected. One glitch arose immediately, however. An employee notified the property manager that the water in the bathroom “smells funky and looks cloudy.”

Testing revealed that dangerous Legionella bacteria, which can occur when hot water temperatures decrease and disinfectants (chlorine, for example) drop, had colonized the water supply system. “Lengthy building closures stagnant water in the piping, making it unsafe for people or commercial activities to use when buildings reopen,” says Bob Hillier, President of Paul Davis of Greater Houston. “This customer was fortunate that the appearance and odor flagged poor water quality. Often water with dangerous pathogens looks and smells perfectly clean.”

To avoid this unpleasant and costly problem, Hillier recommends several actions prior to reopening a business or commercial facility served by public water systems. He advises following the steps in order of listing:

Flush service lines that run to the building.
Flush hot and cold-water lines at all points of use, running hot water until maximum water temperature is reached. Time needed to adequately flush the system depends on plumbing design, number of points of use and building size.
Clean water-using devices such as ice-making machines (discard multiple batches of ice), toilets and water tanks.
Verify that flushing has been successful by testing water quality professionally. Several rounds of testing at intervals may be necessary to verify safety.
If testing results indicate water quality issues, advise building occupants and post cautionary signage until water quality is restored.

And if the warehouse had had its own water system, as many schools, recreational facilities and manufacturers do? Page 4 of this informative booklet published by the U.S. Environmental Protection Agency provides useful guidance for the more complicated procedures that are necessary.

The warehouse property manager now knows that, if lengthy closures occur in the future, potable and non-potable water system maintenance must continue while the facility is idle: flushing hot and cold-water lines regularly, regulating hot water temperatures and servicing water treatment systems and water-using equipment. Further, the manager better understands the parameters that help him protect his water system: typical temperatures, pH and optimal disinfectant levels.

“If you get your water from a public utility, these organizations often provide expert advice on all aspects of water usage,” concludes Hillier, who says that public health departments, too, are invaluable resources if water quality has been compromised. “And if despite your best efforts you experience problems, Paul Davis is ready to help.”