Flushing Guidance for Building Water Systems Following Extended Shelter-in-Place Shutdown
MPWD ensures top water quality for all rate payers with constant testing and proper treatment. The water we deliver is disinfected. However, as the Coronavirus shelter-in-place restrictions incrementally get relaxed and businesses reopen, there are actions that managers of buildings, facilities, and campuses should take to ensure water is safe and tastes good.
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, could 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.
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.
This is especially important for restaurants, schools, gyms, hotels, factories, and other facilities restarting water use after shutdowns. Standard maintenance should be conducted to ensure 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 MPWD’s distribution system.
Available Guidance Resources
- SFPUC "Flushing Guidance for Building Water Systems Following Extended Shutdown" (PDF) CLICK HERE
- California Water Service "Reopening Buildings After Low or No Water Use" (PDF) CLICK HERE
- USEPA "Restoring Water Quality in Buildings for Reopening Checklist" (PDF) CLICK HERE
- EBMUD "Ensuring Water Quality for Business Reopening" Fact Sheet (PDF) CLICK HERE
- Centers for Disease Control and Prevention Guidance (website) CLICK HERE
- Environmental Protection Agency Guidance (website) CLICK HERE
- American Water Works Association Guidance (website) CLICK HERE
- International Association of Plumbing and Mechanical Officials Guidance (PDF) CLICK HERE
If you have questions about your water quality, please call MPWD at (650) 591-8941 or contact us here.