Guidance for Reopening Buildings

Returning to a commercial building or property that has been shut down or significantly reduced water use? Flush pipes to replace the water inside the building with fresh water, and clear any sediment or stagnant water from pipes to reduce health risks. Depending on the building size and water pressure, flushing may need to occur in segments (e.g. on different floors or in individual rooms).

  • Turn on faucets and showers (hot and cold taps) at full flow for 5-10 minutes, longer if it’s a bigger building. Flush hot water until it reaches its maximum temperature.
  • Run at least one empty load in dishwashers, let drinking fountains run, and replace ice in ice makers.
  • After flushing, replace any filters.

While the District meets all primary drinking water standards, water that has entered a building and remains stagnant will decline in water quality over time. Buildings and large service connections like commercial properties and institutions that shut down or significantly reduce water use have an increased risk of Legionella growth, and leaving water to sit in pipes for prolonged periods can result in the leaching of lead and copper from pipes.

For more information provided by the Centers for Disease Control and Prevention, including industry specific guidance for businesses, hotels, pools and more visit