Show All Answers

1. What is the difference between inflow and infiltration?

Both words are used to describe "clean" rainwater entering the sanitary sewer system but they refer to different ways that the water gets into the system.  Inflow means water that enters through improper connections (i.e. gutter downspouts tied into sewer lines), or surface openings (i.e. broken cleanout covers, manhole lids).  Infiltration refers to ground water that gets into the system through cracked or broken pipes below the ground.

2. Why is it bad for rainwater to get in the sanitary sewers?

Everything in the sanitary sewer system goes to the Town's wastewater treatment plant.  The size of the treatment plant, as well as all the pipes in the sewer system, are sized based on the number and type of customers connected to that system.  The Town recently completed a $40 million dollar upgrade of their wastewater treatment plant to increase its capacity to 5.3 million gallons per day.  However, even with this expansion, the plant can receive more wastewater than it can handle during heavy rains.  People don't use their sinks and toilets more when it rains, so all that increased flow in the sewer system is coming from inflow and infiltration.  If the sewer pipes or the treatment plant receive more flow than they can handle, then untreated sewage backs up into houses and overflows into streets and streams.  

3. Can my sump pump be connected to the sanitary sewer?

No.  Sump pumps are designed to collect ground water from around basements and foundations and that water is considered "clean" and does not need to be treated like sewage.  Sump pump lines should drain to your yard - away from your foundation - or to the street.

4. Is it okay for my roof downspouts to connect to the sanitary sewer?

No.  Roof downspouts, like sump pump lines should drain to the yard - away from the foundation - or to the street.  During a 1" rainfall event, an average sized roof can produce five times as much runoff water as a family of four would use in a day.

5. What can I do as a homeowner to help reduce I & I?

Check your gutter downspouts and/or sump pump to make sure they are not connected to the sewer pipe that runs from your house to the street.  If your downspouts go into the ground and you don't see water flowing into the yard or through the curb when it rains, there's a chance they are connected to the sanitary sewer.  You should always know where your sump pump drain is so you can keep the end of the pipe clear and avoid backups that may damage the pump.  Also, if you know where the cleanout is on your sewer service line, make sure it has a tight fitting lid on it to keep rainwater out.

6. What is the Town doing to reduce I & I?

The Town regularly performs the following inspection and reduction measures:

• Camera inspection of sewer lines and laterals - Running a camera through the lines, especially during wet weather, can help find areas with damaged pipes which let groundwater flow into the system.  Cameras can also spot laterals that have excessive flows in them, indicating a damaged pipe or an improper connection.
• Manhole rehabilitation - Older manholes can become cracked an leaky, especially at joints or around pipe connections.  Depending on the severity of the damage, a manhole may be able to be coated from the inside to restore it to a waterproof condition.
• Smoke testing - Smoke testing involves filling a section of the sewer piping with smoke and watching for areas where the smoke appears above ground.  This colorless, non-staining smoke will make its way through larger cracks in the pipes and up through the ground to help pinpoint areas that need to be replaced.  Also, smoke coming up through a gutter downspout would indicate an improper connection to the sanitary sewer.
• Manhole cover replacement - Older manhole lids have large holes that go all the way through the lid to allow picks to pry the lid up.  If these lids are in a low spot in the street, the water collecting on top of them will drain through the lid and into the sewer system.  The Town is in the process of replacing these lids with watertight lids.  Watertight lids have pick holes that don't go all the way through the lid and also have a flexible gasket around the edge.