The chlorine and ammonia added to disinfect the water at the water treatment facility slowly begins to dissipate over time. Without them, microorganisms can grow in pipes, fixtures and tanks.

Any device that water passes through needs to be flushed. This includes:

• water fountains
• ice machines
• soda machines
• water heaters
• dishwashers
• coffee makers

Replace all point-of-use filters, including the filter in refrigerators. Keep water heaters set at their designated temperature (ideally at or above 120°F). Continue routine maintenance on hot tubs and swimming pools.

The American Water Works Association recommends a thorough flushing process that includes running water through all faucets and spigots for anywhere from 10 to 30 minutes.

• Flush the cold water lines first and then the hot water lines.
• Run the water in one direction, from the building’s entrance to its outer points.
• Flush all water-using appliances like ice machines and dishwashers.
• Water treatment devices like filters and water softeners also need to be cleaned and flushed.

Flushing for a longer period of time or more than once may be necessary. Any piece of equipment where water is stored should be drained and flushed with cold water. The sooner you can start this process the better.

A building’s water system starts at the meter and continues through the owner’s service line into the building. It includes all the building’s plumbing, storage tanks, and fixtures, including fire suppression systems.

This is an unprecedented event for the plumbing systems in many buildings. Undesirable taste and odor, combined with the potential risk of illness, would require immediate action and further postpone reopening. That’s why it’s vital to flush the stale water out before the buildings reopen.

The CDC is offering the following guidance: 

• Developing a comprehensive water management program;
• Making sure your water heater is properly maintained and the temperature correctly set;
• Cleaning all decorative features such as waterfalls or fountains;
• Ensuring hot tubs and spas are safe for use;
• Cleaning safety equipment such as eye wash stations and safety showers;
• Checking with your local utility to request a water quality check; and
• Flushing your building’s water system.

That’s one step in the process for reopening but every building is different. It’s important to take an inventory, examine the parts of your water system, and coordinate a specific plan to address every section where water may have collected during the stay-at-home period.

Inspect mechanical equipment such as cooling towers, boilers, pumps, and backflow preventers. Clean showerheads, faucets, and anything else that sprays water and could send bacteria into the air. If your business caters to a clientele that includes people who have chronic health conditions or are immunocompromised, collect water samples and deliver them to a laboratory for analysis.

For buildings built before lead solder was banned in 1986, water stagnation can present a problem. When water sits in pipes for an extended period, some leaching of copper (from copper pipes) and lead (from the solder) can occur.

The same flushing practices recommended above will work to clear pipes and faucets. This is especially important for facilities that serve infants and toddlers, school-age children, or pregnant or nursing mothers.

These recommendations are for larger buildings such as hotels, offices, stores, restaurants, churches, college campuses and schools. But experts say it’s always smart for small businesses and homeowners to protect themselves from the potential impacts of stale water when your home or business has been vacant.

Make it part of your regular routine. That means following local and state guidelines for household water use and following manufacturer’s instructions for cleaning, disinfecting, and maintaining any device or appliance that uses water.