Inflow and Infiltration (I/I) is the introduction of water into a municipal sewer system as the result of direct inflow from external sources such as a drain pipe or sump pump, or infiltration of groundwater due to leaks in the infrastructure.

Recently, the Town of Tyngsborough completed a comprehensive study of the inflow and infiltration problems being experienced across the town.  The evidence clearly points to direct inflow primarily caused by individual home owners discharging basement sump pumps into a sink or by direct connection to the wastewater service connection.

The Sewer Department has confirmed this problem with the use of a video camera inserted in the sewer main. The town’s sewerage flow is measures at metering stations at the town’s borders with Lowell, Dracut and Chelmsford.  The Sewer Department receives invoices from these communities that reflect the number of gallons per day passing through the metering stations.

This problem has to be addressed for several reasons:

•  to keep the User Fees down

•  to free up capacity in the system that we have already paid for

•  to respond to the state demands for the removal if inflow and infiltration at a rate of 2:1 for all new sewer extensions permitted in town

•  to allow the town to remain eligible for low interest loans through the Revolving Fund

•  To increase the life cycle of the expensive pumps that work 24/7 to move sewerage through the system

Initially, we are launching this public awareness campaign to encourage homeowners to discharge their sump pumps to the street drainage system, if one is available.  We understand the inconvenience this may cause.  However, it is costing you money.

Hopefully, a volunteer effort will resolve the matter to the extent practicable.  The Sewer Commission has a responsibility to the sewer users to get the most for their dollar. Paying to have drainage water processed through the Greater Lowell Wastewater Treatment Facility, is not the best use of your dollar.

If you have any questions or would like to learn more, please contact Allen Curseaden at

978-649-2300  Ext. 134.

Your cooperation is greatly appreciated.
Tyngsborough Sewer Commission