Flushing is routinely conducted in spring and fall because the demand for water tends to be at its lowest and cold weather is not an issue.

Not only does flushing help us identify any hydrants for need of replacement or maintenance it enhances water quality.  It allows sediment built up in the water mains, especially dead ends and low-flow areas, to work its way out of the system. The high velocity of water causes a scouring action that draws the sediment out. 
Please make arrangements to minimize your water use during this time period to avoid drawing sediment into your water service. It is very important that all customers check their water before washing clothes to avoid rust discoloration.  Some customers will experience rusty or black water caused by naturally occurring iron and manganese minerals. These non-health-threatening minerals may cause staining of laundry and plumbing fixtures that the District is not liable for. To minimize these effects avoid using products that contain chlorine (including automatic dishwashing detergents). This discoloration should only last a day or two while flushing in your immediate area.  The Water Department recommends that when the water clears up that you flush out your hot water heater to remove any accumulated sediments.  

Public notification of the flushing is key to minimizing disturbances in customers’ homes. DWSD publicizes the general areas expected to be impacted one to two weeks before the flushing starts. It is important to remember that flushing can cause discoloration in other areas of Town not directly being flushed and street listings published only indicate the general areas being worked in.  

Click here to read the District's by-law regarding dirty water. 
MassDEP fact sheet on water main flushing