Water System Restoration

Business

Each building is different and will require different actions based on its plumbing systems, use patterns, and source of water supply. Pay particular attention to high-risk equipment such as heating and refrigeration systems, sinks, safety equipment, pools and hot tubs, water features, etc. For more information, refer to the resource links below for recommendations from recognized water industry professionals.

Prepare to flush water pipes:

1. Remove and clean faucet aerators and showerheads. Leave off during flushing.
2. Remove point of use filter cartridges, such as the filter in refrigerators, and consider replacing.
3. Discard ice from ice makers and discard two to three additional batches.

Flush water pipes and internal plumbing:

1. 1. Begin with fixtures where the water first enters the business.
   2. Systematically flush from bottom to top of the building.
   3. Flush cold water lines first, then the hot water lines.
   4. Flush each fixture at a full flow rate for five minutes or until a noticeable change in water temperature occurs.
   5. Run dishwashers empty for two to three cycles.

Test water

1. 1. When testing yourself (chlorine, pH, temperature, conductivity), use test equipment with EPA approved methods. Many test kits sold at home improvement stores do not provide highly accurate results but do provide a general indicator.
   2. When testing professionally, ensure that you work with a State of Washington laboratory accredited for drinking water.
      • WA DOE Accredited Laboratories
      • CDC ELITE Program for Legionella

Residential

It is always a good practice to flush your water pipes and faucets for 30 seconds after periods of low or no flow, such as while you are at work or overnight while you are sleeping.  This flushing helps remove routine corrosion particles from the piping and freshens the water.

There are also other steps to take after an extended period of discontinued service (e.g., weeks or months.) A thorough flushing process is appropriate in such situations.

Prepare to flush water pipes:

1. 1. Remove and clean faucet aerators and showerheads. Leave off during flushing.
   2. Remove point of use filter cartridges, such as the filter in refrigerators, and consider replacing.
   3. Discard ice from ice makers and discard two to three additional batches.

Flush water pipes and internal plumbing:

1. 1. Begin with fixtures where the water first enters the home.
   2. Systematically flush from bottom to top of the house.
   3. Flush cold water lines first, then the hot water lines.
   4. Flush each fixture at a full flow rate for five minutes or until a noticeable change in water temperature occurs.
   5. Run dishwashers and clothes washers empty for two to three cycles.

Test your water

When testing yourself (chlorine, pH, temperature, conductivity), use test equipment with EPA approved methods. Many test kits sold at home improvement stores do not provide highly accurate results but do provide a general indicator.

Normal Water Chemistry Parameters

• Average pH = 8.59 (expected range is 8.0 to 9.0)
• Average chlorine residual = 1.11 ppm (expected range is 0.7 to 1.2 ppm)
  • ppm = parts per million

While temperature may change seasonally, chemistry values remain stable.

Additional Resources

Helpful guidance from water industry professionals.

• State of Washington Department of Health (DOH) – Drinking Water
  • DOH Guidance for Legionella and Building Water System Closures
• Centers for Disease Control – CDC
• American Water Works Association
• Purdue University Links
  • Example Flushing Plans from Purdue University
• Environmental Protection Agency