Since the soil in your landscape contains organic matter, microbes, fertilizers and other potentially harmful chemicals, the EPA has mandated that all irrigation systems be equipped with an RPZ device. This device prevents the water in your sprinkler system from mixing with the water in your house and with the city’s main water line. Illinois law requires that the RPZ on your irrigation system, pool, boiler, etc. is tested annually by a CCCDI licensed plumber to ensure that it is working properly. This test is mandatory – not optional. Advanced Sprinkler Systems, Inc. has licensed professionals on staff who can test, certify and service your RPZ for you.