If your building has been closed or only a few people have been using it, the water in the pipes should be flushed before you start up your business again.

“The chemicals that we put in the water to condition it and prevent bacteria growth or corrosion tend to dwindle and go to zero. And you pick up things like bacterial contamination and metals contamination from contact with the plumbing,” said Eric Oswald, Director of the Michigan Department of Environment, Great Lakes, and Energy’s Drinking Water and Environmental Health Division.

That means there could be high levels of lead or copper in the water. The worst case would be Legionella bacteria which can cause Legionnaire’s disease. It kills one out of eleven people who get sick from it, according to the Centers for Disease Control and Prevention.

“EPA recommends and then CDC recommends 140 degrees, turning your water heaters up to 140 degrees, and flushing hot water through the system to kill any kind of bacteria, especially Legionella,” Oswald noted.

Depending on how big your building is, it could take up to 30 minutes with all taps on, cold and hot water, to properly flush the pipes. You can check with your local water department for guidance on how long you should flush the pipes for your size of building.

There’s lots of advice on how to flush your pipes. Here are links to information from the American Waterworks Association (here) and the Centers for Disease Control (here).