The Rocky Mount Water Resources Department is encouraging building owners and managers to freshen the water in their building’s internal plumbing before reopening to the public.

The shutting down of many commercial buildings across the city due the coronavirus pandemic may have resulted in little or no water running through building pipes for an extended period. This may cause discolored water or lower chloramine residual disinfectant, which could cause harmful microorganisms to proliferate.

The stagnant water should therefore be flushed out as fresh water is drawn into the system. The American Water Works Association offers these guidelines for flushing, which will vary depending on the structure — but key elements of existing protocol should include:

  • Remove or bypass devices like point-of-entry treatment units prior to flushing.
  • Take steps to prevent backflow or the siphoning of contaminants into plumbing, such as close valves separating irrigation systems from building plumbing, disconnect hoses attached to faucets
  • Organize flushing to maximize the flow of water by opening all outlets simultaneously to flush the service line and then flushing outlets individually starting near where the water enters the structure).
  • Run enough water through all outlets, such as hose bibs, faucets, showerheads, toilets, etc., removing aerators when possible. Typical durations in existing protocols range from 10-30 minutes for each outlet, but duration varies based on outlet velocity.
  • Flush the cold-water lines first, and then the hot water lines. The hot water tank can be drained directly; it can require roughly 45 minutes to fully flush a typical 40-gallon hot water tank.
  • Replace all point-of-use filters, including the filter in refrigerators.

Additional precautions may be warranted if there is excessive disruption of pipe scale or if there are concerns about biofilm development. Actions that might be warranted include continued use of bottled water, installation of a point-of-use device or engaging a contractor to thoroughly clean the plumbing system.