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Cross Connection Program

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1. How does contamination of water occur?

Water normally flows in one direction from a public water system through a private one, and finally to a plumbing fixture (faucet, garden hose, etc). A pollutant may enter the potable water system if the pressure at the pollution source exceeds the pressure of the potable water source. The reversal of the flow of water is called backflow, and leads to the possible contamination of the public water supply. Backflow may also occur as a result of a sudden loss of pressure in the water system.

2. What can cause backflow?

Backflow is usually caused by a sudden drop of the water pressure in a public water main. This can create a subatmospheric condition. For example, if the pressure drops in a system while a hose is in a bucket of dirty water, that water could backflow into the public water system, potentially contaminating the water for other users. A drop in pressure could be caused by a variety of things, including a water main break or the loss of power at a pump station.

3. What can I do to prevent backflow?

• Keep the ends of your hoses free of any possible contaminants
• If your threaded faucets are not equipped with an in-line protection device, install an approved hose bibb vacuum breaker or other backflow prevention devices
• Never submerge hoses in buckets, vats, sinks, tubs or ponds
• Use spray attachments or valve spray hoses that have a devise to prevent backflow
• Do not connect waste drain pipes from water softeners or other treatment systems directly to the sewer system
• All drains should be air gapped

4. Why do backflow preventers have to be tested?

Mechanical backflow preventers have internal seals, springs and moving parts that are subject to fouling, wear or fatigue. Additionally, mechanical backflow preventers (and air gaps) can be bypassed. All backflow preventers must be tested periodically to ensure that they are functioning properly. A visual check of air gaps is sufficient, but mechanical backflow preventers have to be tested with properly calibrated gauge equipment. This is usually done once each year.

5. Who can test backflow preventors?

For your information, City staff compiled a list of contractors from records of those who have recently performed inspection and testing of backflow prevention devices in the City of Highland Park. Inclusion in the list is not an endorsement or recommendation for any of them. Any licensed plumber who is certified by the Illinois Environmental Protection Agency as an inspector is acceptable.

6. Who can I contact for additional information?

For additional information, please contact Don Jensen at the City of Highland Park Water Filtration Plant at (847) 433-4355.

7. Where can I find additional information?

The Illinois Environmental Protection Agency has created several informational guides on cross-connections and specific devices and methods used to prevent backflow:
View the EPA's Cross-Connection Control Methods and Devices
View the Illinois EPA "Cross Connection Rule Summary"
View City Ordinance on Backflow Protection