What is water main flushing?
Water main flushing moves water systematically through sections of a drinking water distribution system, creating a scouring action to clean the line. The increased flow rate scours the water pipe’s inner walls and helps to remove build-up of naturally occurring debris and sediment. The water is discharged through select fire hydrants onto local roads or other surface areas.
The process is critical to the overall maintenance of a distribution system and is one of the most important practices carried out by public drinking water systems to maintain high quality water, improve the carrying capacity of pipes, and ensure proper operation of distribution system components, such as hydrants and valves.
Flushing the water main lines also ensures that fire hydrants are operational and allows the operator to assess the available water pressure and flow rate for firefighting purposes. Flushing at lower velocities can also be used to bring fresh water into a part of the distribution system where the water main ends or deadends.
Water main flushing is typically carried out through either conventional or unidirectional flushing (UDF). The type of flushing performed is based on the specific goals to be achieved within the distribution system.
- Conventional flushing consists of opening hydrants in targeted areas and discharging the water until any accumulations are removed and the water becomes clear. The water moves freely from all directions to an open hydrant. Since there is less flow in a given pipe, velocities may be too low to adequately clean, or scour, the pipes.
- UDF means that water mains are flushed systematically from areas closest to the source water to the outer edges of the water system. Certain valves are closed during UDF operations to minimize disturbance.
Yarmouth is utilizing a UDF flushing plan and will work our way from the center of the system in the vicinity of Station Avenue at Route 6 and work our way outward. Hydrant flushing will continue depending on water availability and system pressures.
How will you be affected?
There may be a slight drop in pressure or noticeable discoloration of the water from the minerals and sediments that are being flushed out. During the flushing operation in your neighborhood, you will be able to see crews flushing the water mains through fire hydrants and ends of water main pipes commonly called blow-offs. Crews will usually direct the water being flushed into appropriate areas to avoid sediment erosion or localized pooling of water, but you may notice water on the street or roadway. There may also be traffic and parking changes because specific hydrants will be used to discharge water.
What should you do?
- Prior to the designated flushing period: consider collecting water for drinking, cooking and other human consumption purpose. Fill a pitcher or pot.
- During the designated flushing period in your area, you may experience water discoloration or sediment.
- Do not use the water in your home, as the water quality may be temporarily reduced at this time and you do not want to draw the water being flushed from the mains into your home piping. Using the water during flushing may result in staining or sediment in laundry, ice machines, dishwasher, bathtubs, or hot water tanks.
If you water appears dirty after the designated flushing period:
- Run a cold water tap closest to your meter without a screen (usually an outdoor spigot or bath tub) for a few minutes up to 15 minutes.
- Keep the tap open until the water runs clear. If you have trouble seeing if the water is clear, fill a light or white colored cup or container to view the water. If the water coming from the tap is not clear after running for 15 minutes, wait 15-30 minutes and try again.
- Do not run a tap that has a water filter connected to it or the sediment may clog your filter. Avoid running a hot water tap because it could draw sediment into your hot water tank.
- If you inadvertently drew discolored water into your home and the staining of clothes or fixtures does occur, rust removal products are available at the Water Department office or most home products stores.
Although inconvenient for in the short term, this program will improve the overall water quality and reliability of the Yarmouth water system. Thank you in advance for your cooperation and we apologize for any inconvenience that this may cause. We appreciate your patience throughout the flushing season!
If you have any questions or concerns, please call the Water Department at 508-771-7921. For more general information, check out the MassDEP Flushing Fact Sheet.