Learn about new ways to improve your code research process.
Join our webinar
Heads up: There are no amended sections in this chapter.
  1. General. All materials used for drainage systems and clear water vacuum waste systems shall comply with Appendix A.Table A (Approved Building Drainage/Vent Pipe).
  2. Corrosive Waste. If corrosive waste is discharged to the drainage system, or if soil conditions are corrosive, only piping material listed in Appendix A.Table A(Approved Building Drainage/Vent Pipe) and approved for use with corrosive material shall be used. Fittings shall be of the same material as piping. No other material (piping, fitting, etc.) shall be used unless its use is approved in writing by the Department prior to installation, in accordance with Section 890.1940.
(Source: Amended at 38 Ill. Reg. 9940, effective April 24, 2014)
  1. Drain — Underground. A building drainage system installed in the ground shall be of cast iron, copper Type "K", or non-metallic Schedule 40 or heavier. Drains shall be installed on a continuous bed of undisturbed earth or granular fill so as to support the pipe and fittings.
  2. Existing Drain and Sewer Installation. Existing drain, waste, vent and sewer may be used in the renovation of the plumbing system of an existing structure if they are in serviceable condition and the materials comply with Appendix A.Table A (Approved Building Drainage/Vent Pipe and Approved Materials for Building Sewer).
  3. Freezing. No soil or waste pipe shall be installed or permitted outside of a building or in an exterior wall unless the piping is protected from freezing. This does not prohibit a soil or waste pipe from extending from a manufactured or mobile home unit to an approved point of discharge, provided that the waste line is protected from freezing.
  4. Dead Ends. Dead ends shall be avoided in a drainage system, except where necessary to extend the system to install a cleanout in an accessible location. A dead end intended for future connection (extension) that is more than 2 feet above a floor or more than 10 feet horizontally from the nearest vented connection shall have a vented connection to the outside atmosphere. (See Appendix J.Illustration A.)
  5. Horizontal Drainage Piping. Horizontal drainage piping shall be installed at a uniform grade.
  6. Small Piping. Horizontal drainage piping of 3 inches diameter or less shall be installed with a grade of at least 1/4-inch per foot.
  7. Large Piping. Horizontal drainage piping larger than 3 inches but less than 8 inches in diameter shall be installed with a grade of at least 1/8-inch per foot. For piping 8 inches or larger in diameter, the grade is determined by the number of drainage fixture units connected to the drain pipe. (See Appendix A.Table G.)
  8. Minimum Velocity. If conditions do not permit building drains to be installed with a grade as great as that specified in subsections (f) and (g), a lesser grade may be used, provided that the computed velocity will not be less than 2 feet per second.
  9. Changes in Direction. Changes in direction shall be made in drainage piping by the use of 45 degree wyes, long sweeps, short sweeps, quarter, fifth, sixth, eighth, or sixteenth bends, or by a combination of these fittings. Single and double sanitary tees and short sweep quarter bends shall be used in drainage lines only where the direction of flow is from the horizontal to the vertical and may be used for making necessary vertical offsets between the ceiling and floor above. (See Appendix J.Illustrations B, C and D.) Exception: A short sweep drainage quarter bend of less than 3 inches diameter and placed in a horizontal to horizontal position for a stack vent arm may be used to receive graywater.
  10. No fittings having a hub in the direction opposite to flow, or tee branch, shall be used as a drainage fitting. No running threads, bands or saddles shall be used in the drainage system. No drainage or vent pipe or fitting shall be drilled or tapped.
  11. No fitting, connection, device or method of installation shall be used that obstructs or retards the flow of water, waste or air in the drainage or venting system by an amount greater than the normal frictional resistance to flow. The enlargement of a 3-inch closet bend or stub to 4 inches shall not be considered an obstruction if it is necessary to increase the bend or stub at the floor line to 4 inches in diameter to accommodate the water closet outlet.
  12. Fixture Connections. Branch wastes and fittings for circuit-vented fixtures shall be installed so that the fixture drain enters the side of the branch drain. (See subsection (i) and Appendix J.Illustration E.)
  13. Back-to-Back Fixtures. Back-to-back fixtures shall be installed with fittings that will prevent mixing of the discharge prior to a change in direction of flow of the discharge from each fixture, or shall be installed with fittings especially designed to eliminate throw-over or backflow of the discharge from one fixture to the other fixture.
  14. Location of Drains. All building drains, branches of building drains, building sewers or any sanitary sewers shall be located at least 50 feet from a well or buried suction line, except that, when cast iron pipe with mechanical or compression joints or Schedule 40 PVC pipe with solvent weld and watertight joints is used for the building sewer, the drains shall be located at least 10 feet from a well or buried suction line.
  15. Backwater valves may be installed in the building storm drain or the building drain to prevent backflow into the building, where backflow of storm water or sewage could occur. Backwater valves may be installed in the branches of the building drain that are below grade. Backwater valves, when fully opened, shall have a capacity of at least that of the pipes in which they are installed. Backwater valves shall be installed to be accessible. All backwater valves shall conform to ASME A112.14.1. All bearing parts of backwater valves shall be made of corrosion-resistant material.
(Source: Amended at 38 Ill. Reg. 9940, effective April 24, 2014)
  1. Values for Fixtures. Drainage fixture units (DFUs) (see Appendix A.Table E) designate the relative load of different kinds of fixtures that shall be used to calculate the total load carried by a soil or waste pipe, and shall be used with the tables of sizes for soil, waste and drain pipes for which the permissible load is given in terms of DFUs.
  2. Values for Continuous Flow. For a continuous or semi-continuous flow into a drainage system, such as from a pump, ejector, air-conditioning equipment or similar devices, two DFUs shall be considered to be equal to each gallon per minute (gpm) of flow.
(Source: Amended at 38 Ill. Reg. 9940, effective April 24, 2014)
  1. Maximum Fixture Unit Load. The maximum number of DFUs that may be connected to a given size of building drain, horizontal branch, or vertical soil or waste stack is established in Appendix A.Tables G and H. Exception: As an alternative to using Appendix A.Tables G and H to design and size the building drain, horizontal branch, or vertical soil or waste stack, the system may be designed and sized employing current engineering practices, provided that the design/plans are signed and sealed by an Illinois licensed professional engineer, an Illinois licensed architect or an individual Certified in Plumbing Design (CPD) by the American Society of Plumbing Engineers and approved in writing by the Department.
  2. Minimum Size of Building Drain, Horizontal Branches, Drainage Piping
    1. The minimum size of any gravity building drain shall be 4 inches in diameter.
    2. Pressure-building drains shall not be used where gravity drains may be installed. Pressure-building drains shall be sized in accordance with the ejector pump manufacturer's recommendation, but shall not be less than 2 inches in diameter.
    3. Gravity drained horizontal branches of the building drain shall be sized in accordance with Appendix A.Table H.
    4. No portion of the drainage system installed underground or below a basement or cellar shall be less than 2 inches in diameter. The venting system is excluded from this requirement.
    5. The drainage piping shall not be reduced in size in the direction of flow.
  3. Minimum Size of Soil and Waste Stacks. No soil or waste stack shall be smaller than the largest horizontal branch connected to the stack, except that a 4 inch by 3 inch water closet connection shall not be considered as a reduction in pipe size.
  4. Waste Stacks Serving Kitchen Sinks. In one- or two-family dwellings in which the waste stack or vent receives the discharge of a kitchen-type sink and also serves as a vent for fixtures connected to the horizontal portion of the branch served by the waste stack, the minimum size of the waste stack up to the highest sink branch connection shall be 2 inches in diameter. Above that point the size of the stack shall be governed by the total number of drainage fixture units vented by the stack. (See Appendix J.Illustration F.)
  5. Future Fixtures. If the future installation of fixtures is provided for during initial construction, the fixtures provided for shall be considered in determining the required size of drain pipes and vent piping. Piping provided for future installation of fixtures shall be terminated with a plugged fitting or fittings at the stack so as to form no dead ends. In a multi-story building, when openings are roughed in for future fixtures below the uppermost level, properly sized vent piping shall be connected to the vent system and carried down to the appropriate lower level and be capped or plugged in an accessible location for venting of the future fixtures.
(Source: Amended at 38 Ill. Reg. 9940, effective April 24, 2014)
  1. Offsets of 45 Degrees or Less. An offset in a vertical soil or waste stack with a change of direction of 45 degrees or less from the vertical shall be sized as a straight vertical stack. If a horizontal soil or waste branch connects to the soil or waste stack within two (2) feet above or below the offset, a relief vent shall be installed in accordance with Section 890.1550(c). (See Appendix J: Illustration G.)
  2. Offsets of More Than 45 Degrees. A soil or waste stack with an offset of more than 45 degrees from the vertical shall be sized and installed as follows:
    1. The portion of the stack above the offset shall be sized as for a regular stack based on the total number of drainage fixture units above the offset.
    2. The offset shall be sized as for a building drain. (See Appendix A: Table G.)
    3. The portion of the stack below the offset shall be sized as for the offset or based on the total number of drainage fixture units on the entire stack, whichever is larger. (See Appendix A: Table L.)
    4. The drain offset shall have a relief vent installed as provided in Section 890.1550. In no case shall a horizontal soil or waste branch connect to the soil or waste stack within two (2) feet above or below the drain offset. (See Appendix J: Illustration H.)
  3. Above Highest Branch. An offset above the highest horizontal waste branch is an offset in the stack vent and shall be considered only as it affects the developed length of the vent. (See Appendix J: Illustration I.)
  4. Below Lowest Branch. In the case of an offset in a soil or waste stack below the lowest horizontal branch, no change in diameter of the stack shall be required because of the offset if it is made at an angle of not greater than 45 degrees. If such an offset is made at an angle greater than 45 degrees, the required diameter of the offset and the stack below it shall be determined as for a building drain. (See Appendix A: Table G, and Appendix J: Illustration J.)
  1. Sanitary Wastes below Sewer
    1. Sanitary wastes that cannot be discharged by gravity flow shall be discharged into a gas-tight, covered and vented sump from which the waste shall be lifted and discharged into a sanitary waste drain by automatic sewage ejection pumping equipment. (See Appendix J.Illustration K.)
    2. Sumps and ejectors handling sub-soil drainage and footing drains shall not receive any sewage.
    3. Sumps and ejectors handling sewage shall not receive subsoil drainage and footing drains.
  2. Design. Sump and pumping equipment shall be designed and installed to discharge, during the pumping cycle, all contents accumulated in the sump except for sump contents that must remain in the sump for the continued proper operation of the pumping equipment (e.g., contents needed to submerge or prime the pump) according to the manufacturer's recommendations.
  3. Sub-Drainage. The system of drainage piping below the building drain level shall be installed and vented in the same manner as that of the gravity drainage system.
  4. Duplex Equipment. Sumps receiving the discharge of more than six water closets or 60 DFUs shall be provided with duplex pumping equipment.
  5. Vent Sizes. Building sump vents shall be sized in accordance with Appendix A.Table K.
  6. Connections. No direct connection of a steam exhaust, blowoff, or drip pipe shall be made with the building drainage system waste water. Steam exhaust, blowoff or drip pipes discharged into the building drainage system shall not exceed a temperature of 180 degrees Fahrenheit. When higher temperatures exist, cooling methods shall be provided to reduce the temperature to 180 degrees Fahrenheit or less.
  7. Elevator Pits
    1. Drains connected directly to sewers shall not be installed in elevator pits.
    2. All discharges from elevator sumps shall indirectly discharge to the sanitary sewer or storm drain.
(Source: Amended at 38 Ill. Reg. 9940, effective April 24, 2014)
  1. Required. Any building or structure in which plumbing fixtures or piping is installed in or under a concrete floor to accommodate fixtures on the level of the concrete floor shall have at least one trapped and vented floor drain. Additional floor drains shall be required if the installation of fixtures and appurtenances requires the use of floor drains. In a multi-family dwelling, each unit shall have a floor drain if fixtures and appurtenances installed in the dwelling require the use of a floor drain.
    1. Underground floor drains connected to a building drain or a building sub-drain within 4 feet of a stack shall be individually vented. All floor drains shall be vented as required by Appendix A.Table I.
    2. Each floor drain shall be connected to a sanitary waste drain, except those drains receiving only clear water discharges, which may be connected to the sub-soil drainage system.
    3. Any sump or hub drain for receiving clear water waste shall extend 2 inches above the floor, and all indirect clear water waste lines shall be above the floor level. Any floor drain level with the floor shall discharge to a sanitary waste drain. (See Appendix A.Tables F and I.)
    4. At least one floor drain shall be located in every restroom having a masonry or concrete floor except those for private use.
    5. In hospitals and nursing homes, floor drains will not be required in toilet/bath facilities serving four or fewer individual residents where access to the facilities is direct from no more than two resident rooms. Toilet/bath facilities in hospitals and nursing homes serving rooms with more than four residents or consisting of multiple toilets, lavatories, etc., are required to have floor drains.
  2. Size. Each floor drain shall be sized for its intended use and the surface area that it drains. Any floor drain or drain trap installed below a basement floor or underground shall be no less than 2 inches in diameter.
  3. Accessibility. Floor drains shall connect into traps, shall be accessible and readily cleaned, and shall be located so that they are easily visible.
  4. Provision for Evaporation. Floor drain seals subject to evaporation shall be of the deep seal type, shall be fed by means of a priming device designed for that purpose, or shall be filled with vegetable oil.
  5. Floor Drains in Food Establishments. Floor drains installed in coolers, freezers, refrigerated holding areas, dressing rooms or processing rooms shall meet the following requirements:
    1. Floor drains shall have a minimum inside diameter of 4 inches.
    2. Drainage lines from water closets and urinals shall not be connected with any other sanitary drainage lines having floor drains located in the food service establishments listed in subsection (e).
    3. Floor drains shall be indirectly discharged to the drainage system, or a backwater valve that conforms with the requirements of Section 890.1320(o) shall be installed to isolate these floor drains from other sanitary discharges.
    4. Floor drains shall comply with the requirements of subsections (b), (c) and (d).
(Source: Amended at 38 Ill. Reg. 9940, effective April 24, 2014)
Any piping installed within a building for the purpose of carrying storm water from a roof and connected to a building drain or building sewer shall comply with the requirements of Appendix A.Table A (Approved Building Drainage/Vent Pipe) and Sections 890.910 through 890.930.

(Source: Amended at 38 Ill. Reg. 9940, effective April 24, 2014)
UpCodes Premium
Leverage the most sophisticated code compliance platform.
TRY FREE FOR TWO WEEKS VISIT PRICING