Water Main Flushing Program


APRIL 26 - MAY 6, 2021

During the spring and fall seasons when residents are busy working on their lawns, Concord Public Works (CPW) is busy flushing our 130 plus miles of water main. 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.

Water mains are flushed for several reasons. It allows hydrants to be periodically used and identified for maintenance or replacement and provides an opportunity for tests to be done to determine if water flow and pressure are sufficient.

Most importantly, flushing 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 volume of water causes a scouring action that draws the sediment out. Left alone, this sediment may cause discoloration when water flow changes, ultimately making its way into customer's homes. 

Iron and manganese, which are naturally present in Concord's groundwater, cause the sediment and color. It is recommended not to ingest (drink, cook, or prepare baby formula with) discolored water, but it is safe for activities such as bathing and dish washing.

Every neighborhood gets flushed roughly every other year. Additional flushing is conducted if sediment historically has built up in certain neighborhoods or if a large amount of customers in a certain area have had problems. A well-designed flushing program does not require water to flow from every hydrant. Our goal is to flush water mains, not hydrants.

Public notification of flushing is key to minimizing disturbances in customer's homes.  CPW publicizes the flushing schedule and general areas expected to be impacted one to two weeks before flushing starts.  Look for this information in the Concord Journal, on social media (Facebook and Twitter), via email News and Notices News Flash and on this webpage.

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.

The benefits of unidirectional flushing activities are important to ensure that high quality water is maintained for essential uses like drinking and for adequate fire protection.  Water main flushing also allows for routine exercising of water main valves and hydrant inspection procedures.  

Concord Public Works continues to monitor water supplies around the clock, if water main flushing needs to be postponed Concord Public Works may do so.