Flushing will occur throughout the year, typically Monday through Friday, between 8 am and 5 pm, and occasionally outside these hours, as needed. Flushing a water main can take 20 minutes to an hour, depending on the age, type, and size of the main and the amount of sediment buildup.

Current Flushing Area 

Beginning January 6, 2026

The City of Hillsboro Water Department will be flushing water mains between SE Alexander Street, SE Oaktree Lane, SE Davis Road, and SE Ironwood Avenue.

Flushing will begin January 6, 2026, and last for approximately two weeks. View a full sized map of the R1 Flushing Zone

Beginning January 26, 2026

The City of Hillsboro Water Department will be flushing water mains between SE Lone Oak Street, SE Alexander Street, SE Davis Road, SE Pinewood Avenue, and SE Highwind Lane.

Flushing will begin January 26, and last for approximately two weeks. View a full-sized map of the R2 Flushing Zone. 

Before flushing, crews: 

• Crews will stage equipment and vehicles in the street near a fire hydrant. Cones and flaggers (if necessary) will safely direct the traveling public around the flushing area.
• Place notification signs on streets in the flushing area.
• Place no parking postcards on any vehicles blocking valves.
• Post no parking signage, if needed. 

During flushing: 

• Passerby's may notice a large amount of water from water mains exiting through a fire hydrant into the street, then draining into the City's Stormwater System. View a short video of flushing.
• Water service will not be turned off and you can continue to use water while flushing occurs nearby.
• Flushing may temporarily affect water pressure and stir up sediment in the pipeline, causing discolored water at your taps. Although the discoloration does not pose a health risk, you are encouraged to:     
  • Avoid running the washing machine or dishwasher until flushing is complete.
  • Flush all taps for up to 10 minutes to clear the pipes after flushing operations are complete.
  • Unscrew and clean sediment from faucet aerators, the small screens attached to the base of faucet spouts.
• Please drive carefully around flushing crews and treat them like any other road construction crew.

Flushing Hillsboro's water mains removes buildup to keep water clean, safe, and flowing.

Over time, sediment from mineral deposits and organic matter settles and accumulates in water mains. This buildup can affect the amount of chlorine in the water, cause taste and discoloration issues, and lead to reduced water flow.

Hillsboro Water uses three types of flushing:

• Conventional: Fire hydrants are opened to release water from the water main. 
• Automatic: An automatic flushing device is connected to a fire hydrant and programmed to flush water at certain time intervals. 
• Unidirectional: A large hose is attached to a specific fire hydrant and valves are opened to flush at a high velocity to remove buildup from an isolated section of the water main pipe.  

Flushed water drains into the City’s stormwater system after chlorine has been removed.

Hillsboro Water’s flushing program is supported by the current budget. Water rates and system development charges will not be increased to pay for flushing.