Flushing Guidance and Checklist for Buildings

The City of Hillsboro Water Department delivers safe, high-quality water that is not impacted by the COVID-19 virus to our customers' service connections.

Building owners are then responsible for the water in the building plumbing systems. Water left sitting in pipes when buildings are closed, or in low use situations, will stagnate and may cause water quality problems and health risks, including:

• The growth and spread of Legionella and other harmful bacteria.
• Lower than usual levels of chlorine disinfectant, which keeps water safe from bacteria.
• Leaching of lead and copper out of pipes and fixtures.

The Oregon Health Authority (OHA) advises building owners to take precautions before resuming regular building use to ensure safe water and protect public health.

Oregon Health Authority Tips

1. In general, flush one area and fixture at a time, starting in the basement and working upward to other floors.
2. Remove aerators and flush cold water first, then hot water.
3. Be sure the hot water heater is set to at least 140 degrees Fahrenheit.
4. Consider collecting one or more coliform bacteria samples after flushing and having the samples analyzed by a local water testing lab

Each building is different and will require different actions based on its plumbing system and use patterns. The Center for Disease Control has developed a Guidance for Building Water Systems website with eight steps to take before your business or building reopens. 

And remember—building water management isn’t just for after a long-term closure. Flushing is an ongoing best practice.

• The American Water Works Association has developed flushing instructions.
• The Oregon Health Authority offers guidance for reopening building water systems after prolonged shutdown.
• Purdue University’s Center of Plumbing Safety also has guidance for building owners related to flushing, including example building flushing plans and other helpful materials.

Once you have completed your water system refresh, notify employees and let customers and others using your building know the steps you are taking to ensure the water is safe. Post a sign or send an email—they will appreciate hearing from you.