Municipal Code of Chicago § 18-29-1001.1 Scope.
18-29-1001.1 Scope.
This article shall govern the material and installation of traps, interceptors and separators.
Traps, Separators and Interceptors (18-29-1001 et seq.)
Municipal Code of Chicago tit. 18, ch. 18-29, art. 10
in effectMunicipal Code of Chicago § 18-29-1002.1 Fixture traps.
18-29-1002.1 Fixture traps.
Each plumbing fixture shall be separately trapped by a water-seal trap, except as otherwise permitted by this chapter. The trap shall be placed as close as possible to the fixture outlet. The vertical distance from the fixture outlet to the trap weir shall not exceed 24 inches (610 mm). The distance of a clothes washer standpipe above a trap shall conform to Section 18-29-802.4. A fixture shall not be double trapped. An automatic clothes washer or laundry tub shall not discharge to a trap service or a kitchen sink.
Exceptions:
1. Sections 18-29-1002.1.1 through 18-29-1002.10 shall not apply to fixtures with integral traps.
2. A combination plumbing fixture is permitted to be installed on one trap provided that one compartment is not more than 6 inches (150 mm) deeper than the other compartment and the waste outlets are not more than 30 inches (762 mm) apart.
3. Where sinks are permitted to be directly connected in accordance with the exceptions to Section 18-29-802.1.1 and 18-29-802.1.7, a grease interceptor intended to serve as a fixture trap in accordance with the manufacturer's installation instructions shall be permitted to serve as the trap for a single fixture or a combination sink of not more than three compartments where the vertical distance from the fixture outlet to the inlet of the interceptor does not exceed 30 inches (762 mm), and the developed length of the waste pipe from the most upstream fixture outlet to the inlet of the interceptor does not exceed 5 feet (1525 mm). When the developed length exceeds 5 feet (1525 mm), or more than one fixture or receptacle is connected to an interceptor, each shall be individually trapped and vented. All receptors shall be individually trapped and vented. Wastes exceeding 140°F shall be cooled before draining into any grease interceptor or interceptor or catch basin.
(Amend Coun. J. 10-14-21, p. 37722, Art. X, § 1)
Municipal Code of Chicago § 18-29-1002.1.1 Open plumbing.
18-29-1002.1.1 Open plumbing.
All sinks, lavatories, and laundry trays shall be so installed as to provide for access to traps and waste connections.
Municipal Code of Chicago § 18-29-1002.1.2 Traps underground.
18-29-1002.1.2 Traps underground.
Underground traps shall be provided with accessible and removable clean-outs, except for separate "P" traps into which floor drains, urinals and other fixtures with removable drain strainers discharge.
Municipal Code of Chicago § 18-29-1002.1.3 Animal facilities and barn drainage.
18-29-1002.1.3 Animal facilities and barn drainage.
All wastes from barns, stables, animal facilities or yards for animals shall be intercepted before entering the sewer by an interceptor or catch-basin, which shall be trapped and covered with a tight iron cover, and such catch-basins, if within buildings, shall be provided with a vent not less than 3 inches (75 mm) in diameter carried through the roof. All floor drains and wash racks shall be provided with deep seal traps and heavy strainers.
Municipal Code of Chicago § 18-29-1002.1.4 Basement floor drains.
18-29-1002.1.4 Basement floor drains.
Basement floor drains shall connect into a trap so located and constructed that it can be readily cleaned and of a size to serve the purpose for which it is intended but in no case less than 2 inches (51 mm) in diameter. The drain inlet shall be accessibly located.
(Amend Coun. J. 10-14-21, p. 37722, Art. X, § 2)
Municipal Code of Chicago § 18-29-1002.1.5 Backwater valves.
18-29-1002.1.5 Backwater valves.
See Section 18-29-715, Backwater Valves.
Municipal Code of Chicago § 18-29-1002.2 Design of traps.
18-29-1002.2 Design of traps.
Fixture traps shall be self-scouring. Fixture traps shall not have interior partitions, except where such traps are integral with the fixture or where such traps are constructed of an approved material that is resistant to corrosion and degradation. Slip joints shall be made with an approved elastomeric gasket and shall only be installed on the trap inlet, trap outlet and within the trap seal.
Municipal Code of Chicago § 18-29-1002.3 Prohibited traps.
18-29-1002.3 Prohibited traps.
The following types of traps are prohibited:
1. Traps that depend on moving parts to maintain the seal;
2. Bell traps;
3. Crown-vent traps;
4. Separate fixture traps that depend on interior partitions for the seal, except those traps constructed of an approved material that is resistant to corrosion and degradation;
5. "S" traps;
6. Drum traps;
7. Building (house) traps in sanitary sewers.
Municipal Code of Chicago § 18-29-1002.4 Trap seals.
18-29-1002.4 Trap seals.
Each fixture shall have a liquid seal of not less than 2 inches (50 mm) and not more than 4 inches (100 mm), or deeper for special designs relating to accessible fixtures. Where a trap seal is subject to loss by evaporation, a deep-seal trap consisting of a 4-inch (100 mm) seal is required, or other means shall be provided to prevent loss of trap seal. Other means shall include: automatic trap seal primers conforming to ASSE 1018 or ASSE 1044, or vegetable or mineral oil added to the trap.
Municipal Code of Chicago § 18-29-1002.5 Size of fixture traps.
18-29-1002.5 Size of fixture traps.
Fixture trap size shall be not less than the size indicated in Table 18-29-709.1. A trap shall not be larger than the drainage pipe into which the trap discharges.
Municipal Code of Chicago § 18-29-1002.6 Deliberately omitted.
Municipal Code of Chicago § 18-29-1002.7 Trap setting and protection.
18-29-1002.7 Trap setting and protection.
Traps shall be set level with respect to the trap seal and, where necessary, shall be protected from freezing.
Municipal Code of Chicago § 18-29-1002.8 Recess for trap connection.
18-29-1002.8 Recess for trap connection.
A recess provided for connection of the underground trap, such as one serving a bathtub in slab-type construction, shall have sides and a bottom of corrosion-resistant, insect- and vermin-proof construction.
Municipal Code of Chicago § 18-29-1002.9 Acid-resisting traps.
18-29-1002.9 Acid-resisting traps.
Where a vitrified clay or other brittleware, acid-resisting trap is installed underground, such trap shall be embedded in concrete extending 6 inches (152 mm) beyond the bottom and sides of the trap.
Municipal Code of Chicago § 18-29-1002.10 Plumbing in mental health centers.
18-29-1002.10 Plumbing in mental health centers.
In mental health centers, pipes and traps shall not be exposed.
Municipal Code of Chicago § 18-29-1003.1 Where required.
18-29-1003.1 Where required.
Interceptors and separators shall be provided to prevent the discharge of oil, grease, sand and other substances harmful or hazardous to the building drainage system, the public sewer or the sewage treatment plant or processes as required in this article.
Exception: An interceptor or separator shall not be required for:
1. Group R occupancies with six or fewer dwelling units or sleeping units.
2. Sinks in kitchenettes or employee break rooms where no dishwashing machine, oven, microwave oven, stove or range is provided.
(Amend Coun. J. 11-8-12, p. 38872, § 371; Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.1.1 Reserved. Editor's note – Coun. J. 10-14-21, p. 37722, Art. X, § 3, repealed § 18-29-1003.1.1, which pertained to interceptors not required.
Municipal Code of Chicago § 18-29-1003.2 Approval.
18-29-1003.2 Approval.
The size, type and location of each interceptor and of each separator shall be designed and installed in accordance with the manufacturer's instructions and the requirements of this section based on the anticipated conditions of use. Wastes that do not require treatment or separation shall not be discharged into any interceptor or separator. All interceptors shall be installed in an accessible location to permit the convenient removal of the lid and internal contents.
(Amend Coun. J. 11-8-12, p. 38872, § 372; Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.3 Grease interceptors.
18-29-1003.3 Grease interceptors.
Grease interceptors shall comply with Sections 18-29-1003.3.1 through 18-29-1003.3.8.
(Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.3.1 Grease interceptors and automatic grease removal devices required.
18-29-1003.3.1 Grease interceptors and automatic grease removal devices required.
A grease interceptor or automatic grease removal device shall be required to receive the drainage from fixtures and equipment with grease-laden waste located in commercial food preparation areas, such as in restaurants, hotel kitchens, hospitals, school kitchens, bars, factory cafeterias and clubs. Fixtures and equipment shall include pot sinks, prerinse sinks, soup kettles or similar devices, wok stations, floor drains or sinks into which kettles are drained, automatic hood wash units and dishwashers without prerinse sinks. Grease interceptors and automatic grease removal devices shall receive waste only from fixtures and equipment that allow fats, oils or grease to be discharged. Where lack of space or other constraints prevent the installation or replacement of a grease interceptor, one or more grease interceptors shall be permitted to be installed on or above the floor and upstream of an existing grease interceptor.
The Department of Water Management is authorized to require installation of a grease interceptor or other remedial measures for other types of buildings where either:
1. Wastewater discharged to the public sewer contains fats, oils or greases of animal, vegetable or mineral petroleum origin at a concentration exceeding 15 mg/L.
2. The building sewer has a visually evident accumulation of fat, oil or grease of animal, vegetable or mineral petroleum origin which either alone or in combination with other wastes is reasonably likely to be capable of obstructing the flow or interfering with the operation or performance of any part of the sewer system.
(Amend Coun. J. 11-8-12, p. 38872, § 373; Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.3.2 Food waste disposers restriction.
18-29-1003.3.2 Food waste disposers restriction.
No grease interceptor or separator shall receive the discharge from a food waste disposer.
(Amend Coun. J. 7-29-15, p. 3537, § 4; Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.3.3 Additives to grease interceptors.
18-29-1003.3.3 Additives to grease interceptors.
Systems that dispense interceptor performance additives to grease interceptors shall not be installed except where such systems dispense microbes for the enhancement of aerobic bioremediation of grease and other organic materials, or for inhibiting growth of pathogenic organisms by anaerobic methods. Such microbial dispensing systems shall be installed only where the grease interceptor manufacturer's instructions allow such systems and the systems conform to ASME A112.14.6. Systems that discharge emulsifiers, chemicals or enzymes to grease interceptors shall be prohibited.
(Amend Coun. J. 7-29-15, p. 3537, § 4; Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.3.4 Reserved. Editor's note – Coun. J. 10-14-21, p. 37722, Art. X, § 3, repealed § 18-29-1003.3.4, which pertained to construction materials.
Municipal Code of Chicago § 18-29-1003.3.5 Hydromechanical grease interceptors; fats, oils and greases disposal systems and automatic grease removal devices.
18-29-1003.3.5 Hydromechanical grease interceptors; fats, oils and greases disposal systems and automatic grease removal devices.
Hydromechanical grease interceptors; fats, oils and greases disposal systems and automatic grease removal devices shall be sized in accordance with ASME A112.14.3, ASME A112.14.4, ASME A112.14.6, CSA B481.3 or PDI G101. Hydromechanical grease interceptors; fats, oils and greases disposal systems and automatic grease removal devices shall be installed in accordance with the manufacturer's instructions. Where manufacturer's instructions are not provided, hydromechanical grease interceptors; fats, oils and greases disposal systems and automatic grease removal devices shall be installed in compliance with ASME A112.14.3, ASME A112.14.4, ASME A112.14.6, CSA B481.3 or PDI G101.
(Amend Coun. J. 11-8-12, p. 38872, § 374; Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.3.5.1 Grease interceptor capacity.
18-29-1003.3.5.1 Grease interceptor capacity.
Grease interceptors shall have the grease retention capacity indicated in Table 18-29-1003.3.5.1 for the flow-through rates indicated.
Table 18-29-1003.3.5.1
Capacity of Grease Interceptors a
Total Flow-Through Rating (gpm) | Grease Retention Capacity (pounds)
Total Flow-Through Rating (gpm) | Grease Retention Capacity (pounds)
4 | 8
6 | 12
7 | 14
9 | 18
10 | 20
12 | 24
14 | 28
15 | 30
18 | 36
20 | 40
25 | 50
35 | 70
50 | 100
75 | 150
100 | 200
For SI: 1 gpm = 3.785 L/m, 1 pound = 0.454 kg.
a. For total flow-through ratings greater than 100 (gpm), double the flow-through rating to determine the grease retention capacity in pounds.
(Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.3.5.2 Rate of flow controls.
18-29-1003.3.5.2 Rate of flow controls.
Grease interceptors shall be equipped with devices to control the rate of water flow so that the water flow does not exceed the rated flow. The flow-control device shall be vented and terminate not less than 6 inches (150 mm) above the flood rim level or installed in accordance with the manufacturer's instructions.
(Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.3.6 Automatic grease removal devices.
18-29-1003.3.6 Automatic grease removal devices.
Where automatic grease removal devices are installed, such devices shall be located downstream of each fixture or multiple fixtures in accordance with the manufacturer's instructions. The automatic grease removal device shall be sized to pretreat the measured or calculated flows for all connected fixtures or equipment. Ready access shall be provided for inspection and maintenance.
(Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.3.7 Gravity grease interceptors and gravity grease interceptors with fats, oils and greases disposal systems.
18-29-1003.3.7 Gravity grease interceptors and gravity grease interceptors with fats, oils and greases disposal systems.
The required capacity of gravity grease interceptors and gravity grease interceptors with fats, oils and greases disposal systems shall be determined by multiplying the peak drain flow into the interceptor in gallons per minute by a retention time of 30 minutes.
Prefabricated gravity grease interceptors shall be designed and tested in accordance with IAPMO/ANSI Z1001. Manufactured gravity grease interceptors with fats, oils and greases disposal systems shall be designed and tested in accordance with ASME A112.14.6 and IAMPO/ANSI Z1001. Gravity grease interceptors and gravity grease interceptors with fats, oils and greases disposal systems shall be installed in accordance with manufacturer's instructions. Where manufacturer's instructions are not provided, gravity grease interceptors and gravity grease interceptors with fats, oils and greases disposal systems shall be installed in compliance with ASME A112.14.6 and IAMPMO/ANSI Z1001.
(Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.3.8 Engineered gravity grease interceptors (grease catch basin)..
18-29-1003.3.8 Engineered gravity grease interceptors (grease catch basin)..
Engineered gravity grease interceptors, which are designed by a registered professional engineer or are constructed in compliance with Department of Water Management standards, shall comply with Sections 18-29-1003.3.8.1 and 18-29-1003.3.8.2 and the capacity requirement of Section 18-29-1003.3.7.
(Amend Coun. J. 7-29-15, p. 3537, § 4; Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.3.8.1 Location and construction.
18-29-1003.3.8.1 Location and construction.
A grease catch basin shall be located outside a building and shall be constructed of heavy cast iron or equally durable metal, fiberglass or high-density polyethylene, concrete (precast or monolithic) or brick or concrete block construction with the block or brick laid up in portland cement mortar with walls not less than 5 inches (125 mm) thick, and bottom not less than 2 inches (50 mm) thick. The basin shall be watertight. The basin shall be not less than 36 inches (914 mm) in diameter below the top of the highest inlet pipe. The bottom of the basin shall be not less than 36 inches (914 mm) below the invert of the outlet pipe. The outlet pipe shall be trapped with a catch basin trap and made of a material as required by this chapter. The catch basin trap shall have a minimum seal of 4 inches (100 mm) and shall have an accessible cleanout of a minimum of 3 inches (75 mm).
(Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.3.8.2 Basin cover.
18-29-1003.3.8.2 Basin cover.
The grease catch basin shall be covered with an all cast-iron cover or cast-iron lid in a stone or concrete ring and with a minimum opening of 16 inches (406 mm) diameter. The lid shall not be less than 1/4 inch (6 mm) thick.
(Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.3.9 Direct connection.
18-29-1003.3.9 Direct connection.
The discharge piping from a grease interceptor shall be directly connected to the sanitary drainage system.
(Added Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.4 Deliberately omitted. (Amend Coun. J. 7-29-15, p. 3537, § 4; Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.4.1 Basin cover.
18-29-1003.4.1 Basin cover.
The basin shall be covered with an all cast-iron cover or cast-iron lid in a stone or concrete ring and with a minimum opening of 16 inches (406 mm). The lid shall not be less than 1/4 inch (6 mm) thick.
Municipal Code of Chicago § 18-29-1003.5 Deliberately omitted.
Municipal Code of Chicago § 18-29-1003.6 Volatile waste separator.
18-29-1003.6 Volatile waste separator.
Gasoline, benzine, naphtha, and other volatile, flammable or explosive wastes shall not discharge into a house sewer, public sewer, or sewage treatment plant. Such wastes shall be intercepted in approved triple basins having a liquid retention of not less than 2 cubic feet (0.19 m3) each, and the volatile, flammable or explosive constituents removed. The installer of the triple basins and the owner of the property shall ensure that such triple basins are installed and operated in accordance with the manufacturer's instructions. Every system of basins within buildings shall be constructed of approved fiberglass, a high-density polyethylene, extra heavy cast iron or equally durable material. A heavy iron cover shall be securely bolted into place and made gas-tight with a soft metallic gasket. The outlet from such basins and the inlet of the first basin shall be trapped with a seal of not less than 4 inches (100 mm). The inlet trap of the first basin shall be omitted when floor drains are individually trapped. A vent pipe of not less than 2 inches (50 mm) in diameter shall be connected to the basins, not less than 4 inches above the top of the outlet and extended independently to the outer air.
(Amend Coun. J. 7-29-15, p. 3537, § 4)
Municipal Code of Chicago § 18-29-1003.6.1 Garages.
18-29-1003.6.1 Garages.
In areas of garages where motor fuels are dispensed or where motor vehicles are serviced, each floor drain shall be properly trapped. In other garage areas or parking facilities, floor drains need not be trapped. Floor drains above the level of the basins shall connect to a stack extending independently to the outer air and the vents of the basins shall be connected 6 inches (152 mm) or higher than the lowest floor drain.
Municipal Code of Chicago § 18-29-1003.7 Separation of liquids.
18-29-1003.7 Separation of liquids.
A mixture of treated or untreated light and heavy liquids with various specific gravities shall be separated in approved receptacle. Separators shall be designed in accordance with Sections 18-29-1003.7.1 and 18-29-1003.7.2.
Municipal Code of Chicago § 18-29-1003.7.1 General design requirements.
18-29-1003.7.1 General design requirements.
Oil separators shall have a depth of not less than 2 feet (610 mm) below the invert of the discharge drain. The outlet opening of the separator shall not have less than 18-inch (457 mm) water seal.
Municipal Code of Chicago § 18-29-1003.7.2 Garage and service stations.
18-29-1003.7.2 Garage and service stations.
Where automobiles are serviced, greased, repaired or washed or where gasoline is dispensed, separators shall have a minimum capacity of 6 cubic feet (0.17 m 3 ) for the first 100 square feet (9.3 m 2 ) of area to be drained into the separator. Parking garages in which servicing, repairing or washing is not conducted, and in which gasoline is not dispensed, shall require a triple basin. Areas of commercial garages utilized only for storage of automobiles are required to be drained through a triple basin.
Municipal Code of Chicago § 18-29-1003.8 Sand interceptors in commercial establishments.
18-29-1003.8 Sand interceptors in commercial establishments.
Sand and similar interceptors for heavy solids shall be designed and located so as to be provided with ready access for cleaning, and shall have a water seal of not less than 6 inches (150 mm).
Municipal Code of Chicago § 18-29-1003.9 Laundries.
18-29-1003.9 Laundries.
Commercial laundries shall be equipped with an interceptor with a wire basket or similar device, removable for cleaning, that prevents passage into the drainage system of solids 1/2 inch (12 mm) or larger in size, string, rags, buttons, or other materials detrimental to the public sewage system.
Municipal Code of Chicago § 18-29-1003.10 Bottling establishments.
18-29-1003.10 Bottling establishments.
Bottling plants shall discharge process wastes into an interceptor that will provide for the separation of broken glass or other solids before discharging waste into the drainage system.
Municipal Code of Chicago § 18-29-1003.11 Slaughterhouses.
18-29-1003.11 Slaughterhouses.
Slaughtering room and dressing room drains shall be equipped with approved separators. The separator shall prevent the discharge into the drainage system of feathers, entrails and other materials that cause clogging.
Municipal Code of Chicago § 18-29-1003.12 Venting of interceptors and separators.
18-29-1003.12 Venting of interceptors and separators.
Interceptors and separators shall be designed so as not to become air bound. Each interceptor or separator shall be vented in accordance with one of the methods in Article 9.
(Amend Coun. J. 10-14-21, p. 37722, Art. X, § 3)
Municipal Code of Chicago § 18-29-1003.13 Access and maintenance of interceptors and separators.
18-29-1003.13 Access and maintenance of interceptors and separators.
Access shall be provided to each interceptor and separator for service and maintenance. Interceptors and separators shall be maintained by periodic removal of accumulated grease, scum, oil, or other floating substances and solids deposited in the interceptors or separators as often as necessary to ensure efficient operation. Each owner shall keep a written record of all maintenance of the interceptor or separator for the life of the unit, or for a period of five years, whichever is longer. Such record of maintenance shall be made available for review by the department of buildings and the department of water management or their duly authorized representatives. The written record of maintenance shall also be transmitted to the department of buildings or the department of water management, as prescribed by the department, upon request.
(Amend Coun. J. 7-29-15, p. 3537, § 4)
Municipal Code of Chicago § 18-29-1004.1 General.
18-29-1004.1 General.
The materials and methods utilized for the construction and installation of traps, interceptors and separators shall comply with this chapter and the applicable provisions of Article 7. The fittings shall not have ledges, shoulders or reductions capable of retarding or obstructing flow of the piping.
Source: City of Chicago, Municipal Code of Chicago (American Legal Publishing, codelibrary.amlegal.com)URL: https://codelibrary.amlegal.com/codes/chicago/latest/chicago_il/0-0-0-2692580Fetched: 10/24/2026