Sewer System

North Wales Borough Infiltration and Inflow (I&I) Program


What is I&I?

Excess water that flows into sewer pipes from groundwater and stormwater is called Infiltration and Inflow or I&I. Groundwater (infiltration) seeps into sewer pipes through holes, cracks, joint failures, and faulty connections. Stormwater (inflow) rapidly flows into sewers via roof drain downspouts, foundation drains, storm drain cross-connections, and through holes in manhole covers generally as a result of heavy rainfall.

What's Been Done So Far?

The North Wales Borough Collection System Rehab Project has been made possible by financial assistance from the Commonwealth of Pennsylvania, Honorable Tom Corbett, Governor and ratepayers of the NWWA Sewer System. To date, two of the three phases of the program have been completed. The first phase of the program focused on correcting infiltration problems in street manholes and sewer mains within the public roadways. The second phase of the program involved identifying and correcting inflow problems, which typically originate from improperly connected sump pumps, downspouts, parking lot drains, yard drains, and sometimes even cross connections with detention or retention basin drain pipes.

What's Next?

I&I Inspection Van

The third phase of the project involves the repair and rehabilitation of sewer mains and manholes. Work will begin in June 2013 and continue through July 2013. To identify which mains are in need of repair, Authority employees have used special video equipment to survey sewer mains for leaks. During this process the exact locations of residential sewer laterals were also recorded for restoration once the main has been repaired. This map shows which streets in the Borough will be rehabilitated.

The leaky mains will be repaired using a technique known as cured-in-place pipelining (CIPP). CIPP is a trenchless technology, which means that leaky mains can be repaired without the expense of digging up the ground covering a main.

During a CIPP installation, a resin-saturated felt tube made of polyester is pulled into a damaged pipe. It is usually done from a manhole. Little to no digging is involved in this process which makes it a more environmentally-friendly method than traditional "dig and replace" pipe repair methods. Once the tube has been fully inserted into the pipe, UV light or steam is used to cure the resin in the tube and form a tight-fitting, jointless and corrosion-resistant replacement pipe. Service laterals are then restored internally using robotically-controlled cutting devices. Finally, the rehabilitated pipe is inspected by closed-circuit television. Cured-in-place pipe is very durable, with an estimated 100-year design life.

This 1-minute video provides a general overview of the CIPP process.

How Will I Be Kept Informed?

Shortly before the project begins, North Wales Borough residents will receive a letter from NWWA that will include an overview of the project, along with essential contact information and the projected start date of the project. 

Approximately one week prior to the start of work in a designated area, affected residents will receive a phone call advising them about the upcoming work. In addition, door hangers will also be left at residences in affected areas the day before work begins.

Work updates will be posted here throughout the project. Please check back often.

NWWA will be using a contractor to perform this work. Project signs will be posted on the affected streets and the contractor's vehicles will be marked with project signs. The contractors will have NWWA employee name tags and will not require entry to your home. If someone requests entry to your home and you are in doubt, refuse entry and call the police.

If at any time you have questions about the work being done in your area, please call our office at 216-699-4836.

Other Important Information

During this process, it is imperative that water flowing into the sewer lines is blocked. This is so the lining being installed has time to set in place and harden. As such, we ask that you not use water when we are working on your street. In addition, based upon flow conditions, we may need to temporarily block your sewer lateral, or shut off water for a limited time while we are passing by your property. This could be necessary to prevent excessive water or materials in the system while the interlining is being installed.

Additionally, you may notice a slight odor created by the curing process. This odor is harmless and may remind you of plastic cement. In advance of our work, you should make sure that your floor drains and other infrequently used plumbing fixtures have some water in their drainage traps so that no sewer gases or chemical odor enters your home. This is easily accomplished by running water in the sink/fixture or by dumping a little bit of water in the floor drain the day before work takes place.