RPZ (Reduced Pressure Zone) devices are backflow prevention devices that protect drinking water and your municipal water supply from contamination.

RPZ (Reduced Pressure Zone) Devices

RPZ devices prevent contaminants from entering the water supply if reduced pressure exists in the supply piping.  This reduced pressure can be caused by a water leak in the house, house water service break, municipal water main break, or hydrant flushing.  When this happens, contaminants in the supply piping can back up into the drinking water supply. 

Where do these contaminants come from?  A few places.  First, they can come from irrigation systems that spray fertilizer or pesticides on the lawn.  They can also come from boilers or fire suppression systems, where water can sit stagnant or trapped, leading to a build-up of bacteria and increased mineral content from the piping system. 

How an RPZ Device Helps your Water

RPZ devices prevent the water from backing up into the drinking water supply.  When the water pressure drops, the RPZ valve opens up and dumps the water out rather than allowing it to backflow into the drinking water supply. 

Illinois state law requires an RPZ valve if your house or building has an irrigation system, fire suppression system, or large boiler.  There is no “grandfathering,” meaning if you have one of these systems, you need an RPZ valve.

Illinois state law also mandates that your RPZ device be tested once every year by a licensed plumber with a Cross Connection Certification license.  If the device passes, the plumber will forward the certification paperwork to your municipality.