Hydrant Flushing

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.