Section SPS 382.33 - Indirect and local waste piping(1) SCOPE. (a) The provisions of this section set forth the requirements for the installation of indirect waste piping and local waste piping.(b) Indirect waste piping and local waste piping draining the fixtures, appliances and devices having a public health concern, including but not limited to those listed in Table 382.33-1, shall be considered as plumbing and shall comply with the provisions of this section.(2) MATERIALS. Indirect waste piping more than 30" in length and all local waste piping shall be of approved materials in accordance with ch. SPS 384.(3) SIZE. Except as provided in pars. (a) and (b), indirect waste piping more than 30" in length and all local waste piping shall be sized in accordance with s. SPS 382.30. (a) Indirect or local waste piping not exceeding 20 feet in length for refrigerated food display cases may not be less than one inch in diameter.(b) Indirect waste piping, attached to an appliance, appurtenance or equipment through which pressurized waste is discharged, shall be sized in accordance with specifications of the manufacturer of the appliance, appurtenance or equipment. Table 382.33-1
Types of Fixtures, Appliances, and Devices of a Public Health Concern |
Baptismal founts |
Bar and soda fountains |
Boiler blowoff basin outlet drains |
Clothes washers and extractors |
Coffee makers and urns |
Dishwashers |
Egg boilers |
Food preparation sinks |
Food processing equipment |
Ice compartments and ice makers |
Potato peelers |
Refrigerated food display cases |
Refrigerated food storage rooms and compartments |
Steam tables, kettles, and related equipment |
Sterilizers |
Stills |
Vending machines |
Other devices, fixtures, and appliances as approved by |
the department |
(4) INSTALLATION. Indirect waste piping and local waste piping shall be so installed as to permit access for flushing and cleaning.(5) TRAPS. (a)Indirect waste piping.1. Gravity flow indirect waste piping more than 30" in length shall be provided with a trap in accordance with s. SPS 382.32 (4), except indirect waste piping draining a sterilizer shall not be trapped.2. All indirect waste piping draining a refrigerated food storage room, compartment or display case shall be provided with a trap in accordance with s. SPS 382.32 (4).(b)Local waste piping. Local waste piping handling sanitary wastes and more than 30" in length shall be provided with a trap in accordance with s. SPS 382.32 (4). Note: Residential exclusion see s. SPS 325.01 (3).
(6) MAXIMUM LENGTH. Indirect waste piping and local waste piping handling sanitary wastes may not exceed 30 feet in length horizontally nor 15 feet in length vertically. Note: See ch. SPS 382 Appendix for further explanatory material.
(7) AIR-GAPS AND AIR-BREAKS. All indirect waste piping and all local waste piping shall discharge by means of an air-gap or air-break into a receptor. (a)Air-gap installation. The installation of an air gap shall conform to any of the following requirements:1. The distance of an air gap shall comply with one of the following:a. The distance of an air gap serving indirect waste piping one inch or less in diameter and a receptor shall be at least twice the diameter of the indirect waste piping.b. The distance of an air gap between indirect waste piping larger than one inch in diameter and a receptor shall not be less than 2 inches.2. The installation of all air-gap fittings shall comply with ASME A112.1.3.3. The installation of a residential dishwashing machine manufactured air gap shall comply with ASSE 1021.(b)Air-break installation. The air-break between indirect waste piping or local waste piping and the receptor shall be accomplished by extending the indirect waste piping or local waste piping below the flood level rim of the receptor and terminating at an elevation above the trap outlet. Note: See ch. SPS 382 Appendix for further explanatory material.
(8) RECEPTORS. A receptor receiving the discharge from indirect waste piping or local waste piping shall be of a shape and capacity as to prevent splashing or flooding. Receptors shall be installed in accordance with this subsection and shall be accessible. (a)Waste sinks and standpipes. A waste sink or a standpipe serving as a receptor shall have its rim at least one inch above the floor.(b)Floor sinks. A floor sink serving as a receptor shall be equipped with a removable metal basket over which the indirect waste piping or local waste piping is to discharge, or the floor sink shall be equipped with a dome strainer. Indirect waste piping or local waste piping shall not discharge through a traffic grate, but shall terminate over an ungrated portion of the floor sink.(c)Local waste piping. Local waste piping may not receive discharge from another local waste pipe.(d)Other receptors. A plumbing fixture may not be used as a receptor for indirect or local waste piping, except as provided in subds. 1. to 9. 1. The indirect waste piping of a portable dishwasher or water treatment device serving one or 2 outlets may discharge into a kitchen sink of a dwelling unit or to a branch tail piece serving a kitchen sink.2. The indirect waste piping of a residential-type automatic clothes washer or water treatment device may discharge into a laundry tray.3. The indirect or local waste piping serving a cross connection control device or assembly, water treatment device, air conditioner, humidifier or furnace condensate may discharge into a branch tailpiece serving a laundry tray.4. The local waste piping serving a water heater temperature and pressure relief valve, water treatment device, cross connection control device or assembly, humidifier, sterilizer, or a furnace or air conditioner may discharge into the riser of a floor drain when installed in accordance with sub. (7) (b).5. The indirect or local waste piping serving a water heater temperature and pressure relief valve, water treatment device, cross connection control device or assembly, or a furnace or air conditioner may discharge to a floor served by a floor drain so as not to create a health or safety hazard.6. The indirect or local waste piping in a one- or 2-family dwelling serving a water heater temperature and pressure relief valve or water treatment device may discharge through the cover of a clear water sump so as not to adversely affect floats by means of a fixed air gap installed in accordance with subs. (7) (a) 2. and (8).7. The indirect waste piping serving a dental mold grinder may discharge into the tailpiece of a trap serving a sink that is provided with a plaster trap and is installed within 3 feet of the mold grinder.8. A water closet, clinic sink, or urinal may receive the discharge from a mortuary or autopsy table.9. The indirect waste piping serving a dialysis machine may discharge to a water closet or lavatory under all the following conditions:a. The water closet or lavatory is in a patient toilet room of a single occupancy in a healthcare facility.b. The discharge to the plumbing fixture shall be made by either a temporary or permanent fixed 1-inch air-gap that will not impede normal operation of the fixture when not in dialysis mode.c. The discharge to the fixtures shall be limited to a department-approved portable healthcare dialysis appliance and a portable water treatment device specifically for dialysis use. Note: See ch. SPS 382 Appendix A-382.33 (8) (a) to (d) for further explanatory material.
(9) INDIRECT WASTE PIPING REQUIRED. Indirect waste shall discharge to an approved receptor in accordance with all of the following:(a)Boilers, pressure tanks and relief valves. Boilers, pressure tanks, relief valves and similar equipment discharging to a drain system shall be by means of an air-gap. 1. Steam pipes shall not connect or discharge to any part of a plumbing system.2.a. Except as provided in subd. 2. b., wastewater more than 160° F in temperature shall be discharged by means of indirect waste to the plumbing system.b. Steam condensate blow down shall be cooled to 160°F in temperature prior to discharging to a plumbing system.(b)Clear water. When discharging to a plumbing system, all clear water shall discharge by means of an air-gap. (bm)Clothes dryers. A single residential ventless dryer with a maximum discharge of less than 1 gallon per minute may discharge into a 2-inch automatic clothes washer box or standpipe within a dwelling unit. Both the residential automatic clothes washer drain hose and the residential ventless dryer drain hose shall physically fit within the receptor without distortion to either hose.(c)Clothes washers.1. 'Residential types.' Residential-type clothes washers shall discharge into the sanitary drain system by means of an air-break.a. A standpipe receptor may not extend more than 36 inches nor less than 18 inches above the centerline of the trap outlet.b. A standpipe receptor shall terminate at least 26 inches but not more than 48 inches above the floor on which the clothes washer is located.c. The maximum number of washers which may discharge to a trap shall be in accordance with Table 382.33-2.d. Washer wastes shall not be discharged to gutters, troughs, local waste piping, indirect waste manifolds or other similar connections.2. 'Laundries.' Pumped-discharge automatic clothes washing equipment, including residential-type clothes washers, in launderettes, laundromats, and self-service laundry establishments shall have the wastes discharge to a drain system by means of standpipes. The standpipes shall be installed in accordance with subd. 1.3. 'Commercial-type.' Gravity discharge clothes washing equipment shall discharge by means of an air-break or by other approved methods into a floor receptor, trench, or trough.a. The receptor shall be sized to hold one full simultaneous discharge load from every machine draining into the receptor.b. The size of the receptor drain shall be determined by the manufacturer's discharge flow rate and the frequency of discharge. Note: See ch. SPS 382 Appendix for further explanatory information.
c. All wastes from the washers shall flow through an interceptor as specified in s. SPS 382.34 (7). Table 382.33-2
Washer Connections
Trap Diameter | Maximum Number of Washers |
2 inches | 1 machine |
3 inches | 3 machines |
4 inches | 4 machines |
(d)Dishwashing machines. All dishwashing machines shall discharge to the sanitary drain system. 1. 'Residential type.' The indirect waste piping from a residential-type dishwashing machine shall not exceed a developed length of 10 feet. The indirect waste piping from a residential-type dishwashing machine shall be installed in accordance with one of the following methods:a. Where an air-gap or air-break is located below the countertop, the indirect waste piping from the dishwashing machine shall discharge to a standpipe. The standpipe shall be at least 1 1/2 inches in diameter and shall extend at least 15 inches above the trap weir.b. Where an air-gap or air-break is located above the countertop, the indirect waste piping from the dishwashing machine shall discharge to local waste piping. The local waste piping shall connect to the kitchen sink branch tailpiece above the trap inlet, the standpipe or to the dishwashing machine connection of a food waste grinder. When the local waste piping discharges to a standpipe, the standpipe shall be at least 1 1/2 inches in diameter and shall extend at least 15 inches above the trap weir. Where a hose is used for local waste piping, the developed length shall not exceed 18 inches.2. 'Commercial'. Commercial dishwashing machines shall discharge into a sanitary drain system by means of an air-gap or air-break into a trapped and vented receptor. The indirect waste piping may not be more than 30 inches in length.(e)Drips and drain outlets. Appliances, devices and apparatus not defined as plumbing fixtures which have drip or drain outlets, which discharge to the plumbing system, shall discharge into an approved receptor by means of an approved air-gap or air-break.(f)Elevator pit drains.1. All drains serving elevator pits shall discharge to the storm drain system as specified in s. SPS 382.36 (4).2. Drains serving elevator pits shall not connect directly with the storm drain system by means of gravity flow piping.3. A sump may not be located in an elevator machine room.4. A drain serving an elevator pit that discharges to a sump shall have a submerged inlet constructed to maintain a minimum 66 trap seal.5. A sump located in an elevator pit may only receive storm or clear water waste from the elevator pit or the elevator machine room, or both. Note: See ch. SPS 382 Appendix for further explanatory material.
(fm)Elevator threshold drains. Elevator emergency threshold drains provided to meet the requirements of International Building Code s. 3007.3 or 3008.3, as adopted and modified by chs. SPS 361 to 366, may be used only to minimize infiltration of water from fire sprinklers into elevator hoistways. Such drains may not receive other water including wastewater. Elevator threshold drains shall comply with all of the following: 1. In lieu of individual traps, a single trap may serve multiple threshold drains on a single floor serving a single hoistway.2. Where multiple elevator threshold drains are served by one trap, an untrapped threshold drain may serve the cleanout requirements under s. SPS 382.35 (3) (a) and is exempt from s. SPS 382.35 (3) (g).3. Discharge shall be as specified in Table 382.38-1, line 4m.4. A drain stack serving only threshold drains serving elevator door areas may utilize a combination drain and vent system under s. SPS 382.31 (17) (d).5. Elevator threshold drains are exempt from safing requirements under s. SPS 384.20 (4) (b) 9.6. The elevator threshold drain stack utilizing a combination drain and vent as permitted by s. SPS 382.31 (17) (d) may not be combined with other plumbing prior to discharging to the building drain or other discharge points.7. Elevator threshold drain traps shall comply with s. SPS 382.32 (3) (c) 1.8. The drain stack shall be sized to accommodate the anticipated design discharge loads of the automatic fire sprinkler system.(g)Food handling establishments. Plumbing fixtures, devices, appliances, and appurtenances installed in food handling establishments engaged in the storage, preparation, selling, serving, or processing of food shall be installed in accordance with this paragraph. 1. 'Bar and soda fountain sinks.' A bar sink, whether installed for hand washing or other use, or a soda fountain sink may discharge to the sanitary drain system through indirect waste piping. a. Where the indirect waste piping is not trapped, the wastes shall be discharged by means of an air-gap.b. Where the indirect waste piping is trapped, the wastes shall be discharged by means of an air-gap or air-break.2. 'Beer taps, coffee makers, glass fillers and soda dispensers.' The drip pan from a beer tap, coffee maker, glass filler, soda dispenser or similar equipment shall discharge to the sanitary drain system through indirect waste piping by means of an air-break or air-gap.3. 'Novelty boxes, ice compartments and ice cream dipper wells.' Novelty boxes, ice compartments and ice cream dipper wells shall discharge to the sanitary drain system through indirect waste piping by means of an air-gap. a. The indirect waste piping shall not exceed 30" in length.b. The indirect waste piping draining a novelty box or ice compartment may not discharge or connect to the indirect waste piping or local waste piping of any other fixture, appliance or device other than a novelty box or ice compartment.4. 'Refrigerated food storage rooms, compartments and display cases.' Drains serving refrigerated food storage rooms, compartments or display cases shall discharge to the sanitary drain system through indirect waste piping. The indirect waste piping shall drain by gravity to a receptor by means of an air-gap or air-break. Where an air-break is installed, the flood level rim of the receptor shall be at least 2" below the top of the fixture strainer or drain opening in the refrigerated room, compartment or display case.5. 'Enclosed food processing equipment.' Coffee urns, egg boilers, potato peelers, steam kettles, steam tables, vending machines and similar types of enclosed food processing equipment shall be discharged to the sanitary drain system through indirect waste piping by means of an air-gap.6. 'Food preparation.' Open culinary sink compartments for thawing or washing food shall discharge to the sanitary drain system through an independent connection by means of an air-gap. The fixture drain upstream of the air-gap shall not exceed a length of 306. Note: See ch. SPS 382 Appendix for further explanatory material.
(h)Sterilizers. Appliances, devices or apparatus, such as stills, sterilizers and similar equipment requiring waste connections and used for sterile materials, shall discharge through indirect waste piping to the sanitary drain system by means of an air-gap. Note: See s. SPS 382.50 regarding sterilizer wastes.
(i)Cross connection control devices or assemblies. Where a receptor is provided, the vent port discharge from cross connection control devices or assemblies shall discharge to the receptor by means of an air-gap.(j)Vacuum systems-central units. Central vacuum units shall discharge by means of an air-gap or air break.(k)Swimming pools.1. The backwash and drain wastewater from a swimming pool, wading pool or whirlpool shall discharge in accordance with Table 382.38-1.2. The discharge from deck drains serving indoor pools shall be directed to the sanitary sewer via an air-gap.3. The discharge from deck drains serving outdoor pools shall be directed to the storm sewer by way of an air-gap, air-break, or to grade. The distance from the top of the air-break to the pool deck shall be a minimum of 6 inches, terminating at a point above the top of the receptor receiving the deck drain discharge.4. The requirements for sewer connections as specified in ch. SPS 390 applies to all public swimming pools.(10) WATER TREATMENT DEVICES. (a) The waste discharge of a water treatment device to the drain system shall be protected in accordance with s. SPS 382.41 with respect to cross connection control.(b) The indirect waste piping or tubing from a water treatment device shall be of a material conforming to one or more of the standards listed in Tables 384.30-8 or 384.30-11.Wis. Admin. Code Department of Safety and Professional Services § SPS 382.33
Cr. Register, February, 1985, No. 350, eff. 3-1-85; r. and recr. Table 82.33-1 and (9) (g) 5., cr. (8) (c) 3., (9) (g) 6. and (k), Register, May, 1988, No. 389, eff. 6-1-88; r. and recr., (3), am. (9) (c) 1. a., (d) 2. and (g) 4., Register, August, 1991, No. 428, eff. 9-1-91; am. (8) (d) 1., 2. and (9) (g) 3. b., r. (9) (k), cr. (10), Register, February, 1994, No. 458, eff. 3-1-94; correction in (9) (i) 5., made under s. 13.93(2m) (b) 7, Stats., Register, February, 1994, No. 458; r. and recr. (9) (f), Register, April, 1998, No. 508, eff. 5-1-98; correction in (9) (i) 5. made under s. 13.93(2m) (b) 7, Stats., Register, April, 1998, No. 508; r. and recr. (9) (i), cr. Table 82.33-3, Register, December, 2000, No. 540, eff. 1-1-01; CR 02-002: am. (5) (a) 2., (7) (b), (9) (c) 1. b., (e), (g) 6., renum. (8) (a) 1., (9) (a) 2. and (10) to be (8) (a), (9) (a) 2. a. and (10) (a) and am. (9) (a) 2. a., r. (8) (a) 2., r. and recr. (8) (c), (d), (9) (b), (d) 1. and (i), cr. (9) (a) 2. b., (c) 1. c., and (10) (b) Register April 2003 No. 568, eff. 5-1-03; CR 02-129: am. (9) (c) 1. b., r. (9) (d) 3. and table 82.33-3, cr. (9) (k) Register January 2004 No. 577, eff. 2-1-04; CR 08-055: r. and recr. (7) (a), cr. (8) (d) 6. and 7., am. (9) (c) 1. a., b. and (f) 1., r. (9) (c) 1. c. Register February 2009 No. 638, eff. 3-1-09; correction in (8) (d) (intro.) made under s. 13.92(4) (b) 7, Stats., Register February 2009 No. 638; CR 10-064: am. Table 82.33-2 Register December 2010 No. 660, eff. 1-1-11; correction in (1) (b), (2), (3) (intro.), (5) (a) 1., 2., (b), (9) (c) 2. a., 3. c., (f) 1., (g) 1., (k) 1., 4., (10) (a), (b) made under s. 13.92(4) (b) 7, Stats., Register December 2011 No. 672.Amended by, correction in (5)(b) (Note) made under s. 13.92(4) (b) 7, Stats., Register December 2015 No. 720, eff.1/1/2016Amended by, CR 23-006: r. and recr. Table 382.33-1, am. (6), (8) (d) (intro.), 2., 6., 7., cr. (8) (d) 8., 9., (9) (intro.), (bm), renum. (9) (c) 2. (intro.), a., b. to (9) (c) 2., 1. c., d., and am., am. (9) (c) 3. (intro.), c., Table 382.33-2 (title), (f) (title), cr. (9) (fm), am. (9) (g) (intro.), 1., (k) 3. Register September 2023 No. 813, eff. 10-1-23; correction in (8) (d) (intro.), 6., 8., 9. b., (9) (bm), (c) 2., (fm) made under s. 35.17, Stats., Register September 2023 No. 813, eff. 10/1/2023For appliances, devices and equipment not included in this section or other sections contact the department for information and proposed installation review.