The Village of Northbrook owns and maintains two separate sewer systems; one for sanitary sewage and one for stormwater runoff. Sanitary sewage is made up of the waste water from inside homes and businesses from various plumbing fixtures such as sinks, toilets, dishwashers, and washing machines. Stormwater runoff includes water that drains overland from a property as well as that which is collected from streets, parking lots, sump pumps and footing tiles.

Sanitary Sewer System

The sanitary sewer system is made up of 124 plus miles of pipes and 13 lift stations which transport waste water to the Metropolitan Water Reclamation District's (MWRD) sewer system. Once in MWRD's sewer system, sewage is transported to and treated at MWRD's waste water treatment plant in Skokie, Illinois.

Reporting Concerns with a Sewer

If you have any questions or concerns regarding the sewer system, please the Public Works Department through the GONorthbrook Service Request system or by calling 847-272-4711.

Sewer Backups: Contact the Public Works Department immediately at 847-272-4711 during regular business hours (7 a.m. to 3 p.m. Monday through Friday) or the Police Department at 847-262-2060 outside of those hours. Important: Basement flooding (where stormwater is seeping through a window well or your walls) can be reported the same way though please describe the situation to help determine which crew needs to respond.

Sewer Inflow & Infiltration

The Village of Northbrook owns and maintains a 133 mile sanitary sewer system. This system transport wastewater from individual properties to the Metropolitan Water Reclamation District’s (MWRD’s) transmission lines which take it to the Skokie Treatment Plant, where it is processed. As part of its on-going responsibilities and to meet its obligations under MWRD’s Watershed Management Ordinance, the Village must complete inspections of its sewer system as well as private systems to identify and mitigate any defects which may allow stormwater or groundwater from entering the sanitary system.

What is inflow and infiltration ("I&I")?

Inflow and infiltration (often called “I&I”) are the two most common ways that storm or groundwater enter the sanitary system. Inflow is entry from an improperly connected drain (such as a sump pump, foundation drain or house gutters). Infiltration is entry from a defect somewhere in a property’s plumbing or from a crack or break in a service line or sewer pipe. The chart to the right illustrates common sources of I&I.

Why is I&I a concern?

I&I reduces capacity in the sanitary sewer system and, during wet weather, it can overwhelm the system and lead to backups into a property’s basement. Backups can happen anywhere where the system might already be slightly obstructed (by roots or a blockage) and there is too much I&I for the system to handle.

What are the most common types of problems on private property?

The most common types of problems in Northbrook are missing or loose clean out caps, illegally connected downspouts or illegal connections (from sump pumps, foundation drains, etc.). If one of these problems is identified on a property, staff will notify the property owner and provide details about the defect and potential remediation methods. 

What is the Village doing about I&I in the public system?

The Village addresses I/I in the public system through two primary methods: (i) annual and special testing to identify defects as well as cleaning of the system and (ii) completing repairs to sewers and manholes to prevent I/I. These repairs often involve the using of lining, which allows for a thin liner to be inserted into the sewer or manhole to prevent more I/I and reinforce the structure of the sewer or manhole. 

Where can I learn more about I&I?

To learn more about I&I, visit MWRD's website. 

Sewer Smoke Testing

As part of maintaining its sanitary sewer system and to meet the requirements of the Metropolitan Water Reclamation District of Greater Chicago's Watershed Management Ordinance, the Village completes sanitary sewer smoke testing on an annual basis. This page provides a basic overview of the program. 

Frequently Asked Questions Regarding Smoke Testing

What is smoke testing and why is the Village doing it?
Smoke testing is a type of sanitary sewer testing designed to help identify defects and points of potential cross connection (i.e. downspouts connected to sanitary sewers). During this testing, sewer mains are pressurized with non-toxic, non-staining smoke. Contractor crews will be surveying the area where testing is being completed and documenting any areas where smoke is found.

The Village is required to complete this testing as part of the Metropolitan Water Reclamation District's requirements for sewer systems that discharge into their system.

Who will be completing this testing?
The Village's contractor for this work is RMS Utility Services.

How will I be notified regarding when the testing begins?
Two to three days prior to the testing, RMS will place pink door tags in the area to be tested. This notice will include more information regarding testing and answer frequently asked questions. The day prior to testing, the Village will also issue a Northbrook Notify message to the area to be tested. To sign up for Northbrook Notify, please visit this link. 

What should I expect during testing?
During testing, you may see smoke rising out of sanitary sewer manholes, the vent stacks (chimneys) of buildings or the ground. Crews will be surveying the area where testing is being completed and documenting any areas where smoke is found. As part of this, crew members may need to temporarily enter your yard. All crew members will have identification badges and will be wearing company uniforms at all times. A Village staff member will also be present to help answer any questions and monitor work.

A video over-viewing smoke testing can be viewed at this link.

What does the smoke look like?
A video with examples that describes the process can be found at this link. An image can be seen below:

Do I need to be home during testing?
No. However, there is a possibility that smoke may inadvertently enter your home through a dry sewer drain trap. To reduce the chance of this happening, please pour one (1) gallon of water down each of your drains, especially those drains in your basement, upon receipt of the pink door tag that will be placed on your door two to three days before the test on your street. This will help seal the drain traps so the smoke cannot enter. If you are concerned that the smoke in your home may not be related to the smoke testing, please do not hesitate to call the Fire Department at 911.

If you will not be home during the testing but someone will be who has a respiratory problem or might be alarmed or confused if they see smoke, please contact RMS at 888-655-4085 to notify them ahead of time.