Unidirectional Flushing and Swabbing Program

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From October 22-November 24, 2025, the City of Greensboro will expand its unidirectional flushing (UDF) preventative maintenance program by partnering with Hydromax, an outside contractor, to expedite efforts in southern Greensboro.

The additional work takes place in an area of the city roughly bordered by Merritt Drive on the west, Interstate 40 on the north, Freeman Mill Road on the east, and West Vandalia Road and Creek Ridge Road on the south. (View the Unidirectional Water System Flushing Dashboard to view a map of area and status of the work.) City staff will continue ongoing UDF work in adjacent communities throughout the end of 2025.

Schedules may change due to weather as this program is not recommended during freezing weather conditions, when water main breaks are more common.

Unidirectional flushing (UDF) and swabbing are planned, preventative-maintenance methods that improve water quality by removing accumulated sediment from the water distribution system.

Unidirectional Flushing

UDF provides superior cleaning of pipes and uses less water than conventional flushing. The process involves closing valves to direct water flow to a fire hydrant, and flushing that hydrant, which minimizes sediment in the system and creates a higher flow rate.

UDF also provides many secondary benefits. Exercising valves and hydrants prolongs the life of the valves. Flushing can help locate broken valves and hydrants when used during the process. It can also locate closed valves or other obstructions in the water mains and narrow a search area when determining the cause of water quality or pressure issues in a specific location.

Swabbing

Swabbing involves a specialized tool that is forcefully propelled through the water mains to remove sediment.

There should be no adverse effects on the water supply system during either UDF or swabbing. The water is safe. During and for up to a day, customers may experience lower pressure or experience temporary discoloration, taste changes, or odors. Customers should not be alarmed as this is normal. City staff members will monitor the water quality and pressure throughout the process.

Thank you for your patience as we work to improve your water quality!

Timeline & Real-Time Dashboard

In May 2025, UDF and swabbing began in pre-selected areas. The process lasts up to one week and is conducted during normal business hours. View the Unidirectional Water System Flushing Dashboard to stay up to date with the work's progress. Dates and times may change due to weather or last-minute changes in the work schedule.

These programs are not recommended during freezing weather conditions, when water main breaks are more common.

What to Expect

Crews will work in the street to access valves and hydrants. Hydrants will be opened and water will flow into the street. Crews will minimize water pooling and disturbance. Hydrants will not be left unattended during flushing.

Customers within pre-selected areas will receive door hangers the week before crews are in the area. The hangers indicate if water service will be impacted. Water service will only be impacted for a short time during the swabbing process, when a specialized tool is forcefully propelled through the water mains to remove sediment.

You may experience discolored water or lower pressure from your tap. In such cases, limit water use to avoid pulling discolored water into your interior plumbing. If you notice discoloration, run cold water for at least five minutes through a faucet without an aerator, such as an outside spigot or the bathtub, until it is clear. Avoid using your washing machine, dishwasher, or icemaker until the swabbing or UDF is complete. Learn more about water discoloration.

If the discoloration persists, call Water Resources 24-hour Dispatch at 336-373-2033.

We do not anticipate lane closures, but if you see crews in your area, please drive carefully and avoid flowing or pooling water.

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