TITLE 77: PUBLIC HEALTHHome
PART 890 ILLINOIS PLUMBING CODE
CHAPTER I: DEPARTMENT OF PUBLIC HEALTH
SECTION 890.760 PRESSURE TYPE WATER TREATMENT UNITS
Section 890.760 Pressure Type Water Treatment Units
Wash water and rinse water drain lines from water softeners and other types of water treatment units shall discharge through a vertical air gap at least twice the diameter of the pipe, but not less than two (2) inches. Any water softening unit which depends on a venturi created by the flow of water from the water supply line to the softener, for the purpose of siphoning brine solution for regeneration, shall not be required to have a backflow preventer on the water supply line. All other types (those that depend on internal check valves to prevent backflow and/or have the inlet supply of water stopped during regeneration) shall have a double check valve backflow preventer assembly installed on the inlet water supply line.