In the case of a residential or commercial irrigation system, a reduced pressure principle backflow prevention device (RPZ) is required between the potable water supply and the irrigation system. Due to the requirements of the backflow prevention program, these devices are required to be tested annually by a Certified Backflow Prevention Tester. A Certified Backflow Prevention Tester is registered with the Illinois EPA. The annual test ensures that the device is working properly and is a requirement of the area's cross connection control program.
Most licensed plumbing contractors have one or more certified testers in their employ and will be happy to provide this service for you.