Cross Connection/Backflow Prevention Program

2020 Residential Sidewalk Survey

In late 2019 and early 2020, the Village conducted a survey of all residential water customers regarding any potential cross connections that may have at their residence. The Village achieved an over 50% response rate and thanks all those that responded. In order to meet the requirements of the Illinois Environmental Protection Agency, the Village’s contractor, BSI Online, Inc., will be completing a sidewalk survey of any residence that did not respond to ensure the Village has a complete and accurate count of cross connections. Below are some frequently asked questions regarding this survey.

When will the survey begin?

The survey will begin during the week of Monday, April 13. Staff anticipates all work will be concluded by the end of May, weather permitting.

As part of this survey, do I need to take any action?

No. The inspectors will complete all necessary work from the sidewalk. There is no need to schedule an appointment for an inspection or speak with an inspector.

What will Inspectors be doing?

Inspectors will walking along the sidewalks and stopping at any property that did not respond to take note of any existing conditions (sprinkler heads, etc.) and whether a cross connection may exist or be needed. These results will be compared against the Village’s existing list of cross connections to determine if any additional follow-up is needed. 

Please note: Inspectors will not step on to private property or approach you directly. Additionally, inspectors will carry identification, follow all social distancing guidelines and wear masks during this work.

Why is the Village conducting this survey?

Under IEPA regulations, the Village must survey all of its residential and commercial customers about their water usage on a regular basis to identify potential cross connections.This is to verify the Village’s existing backflow device information as well as identify previously unknown devices or places where a device is needed but does not currently exist.

This work is deemed essential as it pertains to an essential government function (delivery of safe water). 

Who can contact for more information?

For any questions, please contact BSI Online at 800-414-4990 or the Village of Northbrook Public Works Department at 847-272-4711.

General Program Information

As part of its on-going responsibilities under Illinois Environmental Protection Agency (IEPA) regulations, the Village must maintain an active cross connection program to prevent backflow. This page answers some of the common questions the Village receives about cross connections and the role they play in our water system. 

What is backflow?

Backflow is the reserve flow of water from an individual water customer’s private system to the public distribution system. This can occur any time there is a pressure change in the system (from a water main break, etc.). If the pressure in the private system becomes higher than in the public system, it can cause water to be suctioned back into the public system. 

While in some cases backflow is not a major concern, it can be in any case where the water in a private system could be non-potable (i.e. non-drinkable). For example, some fire sprinkler systems add anti-freeze to the water in their system to prevent pipes from freezing. If this water was to be drawn back into the public supply, it could contaminate it. 

What are cross connection programs?

A cross connection program is designed to identify potential places where backflow can occur and secure them by means of installing a special backflow prevention device. These devices work by preventing water that has already flowed through the device from reversing course. In Illinois, these programs require that utilities oversee the annual submission of testing certifications for each testable backflow device in their service area and conduct periodic surveys to identify any previously unknown devices or places where a device is required but not currently installed.

Who is Backflow Solutions, Inc.?

Backflow Solutions, Inc (also known as BSI Online) is a backflow device data management firm that has been contracted by the Village to manage its cross connection program. If you have one or more backflow prevention devices, you will receive notices directly from BSI Online regarding when your annual tests are due. Additionally, you will also receive notices from BSI Online about the periodic backflow surveys that the Village must conduct. These notices are legitimate. If you have any questions about notices, please contact BSI Online directly or, if you’re not sure if a notice is legitimate, contact the Public Works Department at 847-272-4711.


Do I have a backflow prevention device?

Residential and commercial properties with irrigation systems, autofilled pools/hot tubs/spas, or fire sprinkler systems are required to have a backflow prevention device. Certain commercial properties may also have additional devices depending on their operations.

For help determining if you have a backflow device, please contact Backflow Solutions.

If I have a backflow prevention device, what do I need to do?

If you have a device, under state regulations, you must have it tested annually. Testing must be done by a certified plumber and be submitted to the Village after the tests are complete. Failure to test a device can result in fines of up to $750 per day.

When do I need to have my device tested?

All devices must be tested on an annual basis, regardless of use. The due date will be the same date each year for each individual customer. When BSI Online mails your first notice, it will include the date of your last test as well as the name and contact information for the plumber who last completed it.

Where can I learn more about backflow?

Below are some important documents regarding backflow and cross connection programs.

Cross Connection/Backflow Prevention Documents