Flushing Your System

As buildings have been shut down or used less frequently, building water quality degradation becomes a silent but serious issue. This is a general roadmap for how to flush contaminants from the building and get the plumbing system water quality back to pre-stagnation conditions. Each building is different, and flushing will need to be tailored accordingly.

What happened in my building water system while the building was out of use?

  • The building water system begins at the meter where water enters the building and includes all plumbing, storage and fixtures to each distal tap.
  • When the water was not used, the disinfectant in the water dissipated. Without the disinfectant, microorganisms grew on pipes, fixtures and tanks. Some of these may cause disease if they are consumed or inhaled as droplets (particularly while showering).
  • The protective scale on pipes could have destabilized. Without the protective scale, toxic metals like lead can dissolve or shear off as particles and end up in water used for drinking or food preparation.
  • Potentially harmful substances such as disinfection byproducts (DBPs) built up.
  • Mechanical equipment such as cooling towers, boilers and pumps may not have received any routine maintenance. Backflow preventers may have missed annual test cycles.

How do I prepare the building for re-occupancy?

  • The best immediate action is to flush the entire building, including all water-using appliances like ice machines and dishwashers. Flushing clears out the low quality water that accumulated during low use and replaces it with high quality water from Greenville Utilities. The fresh water will help mitigate the problems (loss of protective scale and biofilm growth) that emerged while the water was stagnant. If staff are available to flush, start now. Starting flushing now means less deterioration of water quality in the building and a sooner recovery to normal conditions.
  • Inspect mechanical equipment such as cooling towers, boilers, pumps, backflow preventers, etc., and determine if there are any issues regarding their function.
  • Other actions you could take are:
    • Clean showerheads, faucets and other fixtures that can produce aerosols that people could inhale,
    • Develop a water safety plan, a long-term plan for keeping water quality high and protecting building occupants and visitors, and
    • Collect water samples for analysis at a qualified laboratory (only recommended for buildings with specific at-risk populations like children in childcare and elderly people).

What about my residence? Should I flush my home?

Many homes have maintained service or even increased water use as we stay and work at home and do not need to be flushed. When homes are returned to service after an extended period of discontinued service (e.g., weeks or months), an adult should be present in the home to ensure that the meter works, leaks are minimized, wastewater piping is intact, and the building’s plumbing is flushed. A thorough flushing process is appropriate in such situations. Here's how:

  1. Remove or bypass devices like point-of-entry treatment units prior to flushing.
  2. Take steps to prevent backflow or the siphoning of contaminants back into plumbing (e.g., close valves separating irrigation systems from home plumbing, disconnect hoses attached to faucets, etc.).
  3. Organize flushing to maximize the flow of water (e.g. opening all outlets simultaneously to flush the service line and then flushing outlets individually starting near where the water enters the structure).
  4. Run enough water through all outlets (e.g., hose bibs, faucets, showerheads, toilets, etc.), removing aerators when possible. Typical amount of time is 10 - 30 minutes.
  5. Flush the cold water lines first, and then the hot water lines. Note: the hot water tank can be drained directly; it can require roughly 45 minutes to fully flush a typical 40-gallon hot water tank.
  6. Replace all point-of-use filters, including the filter in refrigerators.

I've got questions. Can you help?

We're here to help and are happy to answer any questions you many have.  Please email or call us at 252-329-2160.