Water Quality in Commercial Buildings

DC Water delivers drinking water and conducts routine monitoring throughout the District. Ensuring clean, safe drinking water involves the shared responsibility of DC Water and commercial building owners. Water quality can change when water leaves the main in the street and enters a building. In the distribution system, water continuously flows through pipes. However, water flow in commercial building pipes is generally slower and dependent on water usage. Minimal or no water usage can affect water quality. DC Water provides recommendations to commercial buildings for maintaining high water quality.

Click here to download a brochure about water quality in commercial buildings.

Tips to Ensure Water Quality in Commerical Buildings

Flushing building water systems after periods of minimal or no water usage
  • Commercial buildings are often vacant during weekends and holidays and experience periods of water stagnation - minimal or no water usage.
  • Water stagnation may cause a reduction in disinfection protection and cause increased bacterial growth in the building pipes.
  • Locate the taps on each floor that are furthest from the floor's water service riser and flush the cold water taps for 10 minutes.
  • Flush each fountain for one minute or install fountains with automatic flushing devices.
Routinely change water fountain filters
  • Water filters that are not routinely changed can accumulate impurities and promote bacterial growth.
  • Replace water fountain filters according to the manufacturer's instructions.
Clean and replace faucet aerators
  • Particles can collect in the aerator screen located at the tip of faucets.
  • Routinely remove and clean aerators.
  • Replace aerators every year.
  • Install low-flow aerators to conserve water.
Install lead-free plumbing fixtures
  • Lead-free plumbing can minimize lead from entering the building's drinking water system.
  • Install fixtures and fittings that contain 0.25 percent lead or less.
  • Until 2014, brass faucets and fittings sold in the United States that are labeled "lead free" can contain up to eight percent lead.
Monitor water usage
  • Monitoring water usage can assist building owners in identifying plumbing leaks.
  • High Usage Notification Alerts (HUNA) notify customers when a building's water usage is higher than normal.
  • Building owners can sign up multiple contacts to receive alerts via phone, email and text.
  • Sign up for HUNA alerts by visiting www.dcwater.com/customercare or call 202-354-3600.
  • Install water efficient fixtures labeled as 'WaterSense' to conserve water and reduce water bills.
Annually inspect and test backflow prevention assemblies
  • Commercial building owners are required to install backflow prevention assemblies.
  • Backflow prevention assemblies prevent the reverse flow of water from the building into the public water system.
  • Certified testers are required to annually inspect backflow prevention assemblies and submit reports to the DC Water Cross Connection Program.
Where can I find more information?
For more information about commercial buildings or backflow prevention, see Cross-Connections or contact the Drinking Water Division at 202-612-3440.

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