Returning to service after prolonged outage

Reopening Fact Sheet-050720-01_Page_1.jpgRecommendations for resuming water use for businesses after extended periods of low water use 

EBMUD ensures top water quality for all customers with constant testing and proper treatment. The water we deliver is disinfected, but it’s not sterile.  As the Coronavirus shelter-in-place restrictions incrementally get relaxed and businesses reopen, there are actions that managers of large buildings and campuses should take to ensure water is safe and tastes good.

Water is perishable, just like any food or drink. Fortunately, water quality can be improved with proper cleaning and flushing of the entire plumbing system when a building or facility is returned to service after any prolonged closure.

During the health crisis shutdown, many businesses closed or limited operations. That resulted in water becoming stagnant in pipes and plumbing systems. When water sits in pipes, water heaters, and storage tanks, the chlorine gradually dissipates. Without that chlorine residual in the building’s water systems, microorganisms can grow, causing water quality problems. Some pathogenic microorganisms, notably Legionella, can proliferate inside of a building’s water system and cause serious disease. In addition, the protective scale on the inside of the pipes can destabilize, leading to dissolution of metal pipes.

This is especially important for schools, gyms, hotels, factories, and other facilities that have complicated onsite water systems. Standard maintenance includes checking temperature settings for hot water heaters, and ensuring that tanks, cooling towers, hot tubs, ice machines, soda fountains, dishwashers, and other plumbing components are safe for use.

Flushing clears out low quality water that accumulated during periods of no or minimal water use, and replaces it with high quality water from EBMUD’s distribution system. Special attention should be paid to shower heads, faucets, and other fixtures, which should be thoroughly cleaned.

And this guidance from the Environmental Protection Agency:

Also, there is good guidance from the American Water Works Association (AWWA) and the International Association of Plumbing and Mechanical Officials (IAPMO):

If you have questions about your water quality, please call 510-287-1842 or email

Fact Sheet

Document Type Size
Reopening Fact Sheet PDF <1 MB