Building and business closures for weeks or months reduce water usage, potentially leading to stagnant water inside building plumbing. This water can become unsafe to drink or otherwise use for personal or commercial purposes. EPA recommends that building owners, building managers, and businesses take steps to flush the building’s plumbing before reopening.

Flushing involves opening taps and letting the water run to remove water that has been standing in the interior pipes and/or outlets. The flushing time can vary by the plumbing configuration and type of outlet being cleared.


  • Contact your water utility about local water quality and to coordinate maintenance activities.
  • Check information from your local public health department for any local requirements for reopening.
  • Follow appropriate regulations and policies for worker safety and health.


  • Review how water moves through your building, from the street to each point of use.
  • Inspect the plumbing.
  • Maintain any water treatment systems (e.g., filters, water-softeners) following manufacturer’s instructions.
  • Ensure the hot water system is operating as specified.
  • Flush the service line that runs from the water main to the building.
  • Flush the cold water lines.
  • Drain and clean water storage facilities and hot water heaters.
  • Flush the hot water lines.
  • Flush, clean, and maintain devices connected to the plumbing system following manufacturer’s instructions.

Consider checking water quality parameters to verify that fresh water is being flushed through the entire plumbing system.


  • Notify your building occupants of the status of the water systems and the flushing program.
  • Limit access to or use of the water as an appropriate cautionary phase.
  • Determine if proactive disinfection/heat treatment is necessary.
  • Develop a water management program.

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