International Residential Code 2015 (IRC 2015)

Chapter 1 Scope and Administration

Chapter 2 Definitions

Chapter 3 Building Planning

Chapter 4 Foundations

Chapter 5 Floors

Chapter 6 Wall Construction

Chapter 7 Wall Covering

Chapter 8 Roof-Ceiling Construction

Chapter 9 Roof Assemblies

Chapter 10 Chimneys and Fireplaces

Chapter 11 [Re] Energy Efficiency

Chapter 12 Mechanical Administration

Chapter 13 General Mechanical System Requirements

Chapter 14 Heating and Cooling Equipment and Appliances

Chapter 15 Exhaust Systems

Chapter 16 Duct Systems

Chapter 17 Combustion Air

Chapter 18 Chimneys and Vents

Chapter 19 Special Appliances, Equipment and Systems

Chapter 20 Boilers and Water Heaters

Chapter 21 Hydronic Piping

Chapter 22 Special Piping and Storage Systems

Chapter 23 Solar Thermal Energy Systems

Chapter 24 Fuel Gas

Chapter 25 Plumbing Administration

Chapter 26 General Plumbing Requirements

Chapter 27 Plumbing Fixtures

Chapter 28 Water Heaters

Chapter 29 Water Supply and Distribution

Chapter 30 Sanitary Drainage

Chapter 31 Vents

Chapter 32 Traps

Chapter 33 Storm Drainage

Chapter 34 General Requirements

Chapter 35 Electrical Definitions

Chapter 36 Services

Chapter 37 Branch Circuit and Feeder Requirements

Chapter 38 Wiring Methods

Chapter 39 Power and Lighting Distribution

Chapter 40 Devices and Luminaires

Chapter 41 Appliance Installation

Chapter 42 Swimming Pools [Electrical Provisions]

Chapter 43 Class 2 Remote-Control, Signaling and Power-Limited Circuits

Chapter 44 High-Velocity Hurricane Zones

Chapter 45 Private Swimming Pools

Chapter 46 Referenced Standards

Appendix A Sizing and Capacities of Gas Piping

Appendix B Sizing of Venting Systems Serving Appliances Equipped With Draft Hoods, Category I Appliances, and Appliances Listed for Use With Type B Vents

Appendix C Exit Terminals of Mechanical Draft and Direct-Vent Venting Systems

Appendix D Recommended Procedure for Safety Inspection of an Existing Appliance Installation

Appendix E Florida Standard for Mitigation of Radon in Existing Buildings Effective: June 1, 1994

Appendix F Florida Standard for Passive Radon-Resistant New Residential Building Construction

Appendix G Piping Standards for Various Applications

Appendix H Patio Covers

Appendix I Private Sewage Disposal

Appendix J Existing Buildings and Structures

Appendix K Sound Transmission

Appendix L Permit Fees

Appendix M Home Day Care—r-3 Occupancy

Appendix N Venting Methods

Appendix O Automatic Vehicular Gates

Appendix P Sizing of Water Piping System

Appendix Q Reserved

Appendix R Light Straw-Clay Construction

Appendix S Strawbale Construction

Appendix T Recommended Procedure for Worst-Case Testing of Atmospheric Venting Systems Under N1102.4 or N1105 Conditions ≤ 5ACH50

Appendix U Solar-Ready Provisions—detached One- And Two-Family Dwellings, Multiple Single- Family Dwellings (Townhouses)

Plumbing fixtures, faucets and fixture fittings shall have smooth impervious surfaces, shall be free from defects, shall not have concealed fouling surfaces, and shall conform to the standards indicated in Table P2701.1 and elsewhere in this code.

TABLE P2701.1


Air gap fittings for use with plumbing fixtures, appliances and appurtenancesASME A112.1.3
Bathtub/whirlpool pressure-sealed doorsASME A112.19.15
Diverters for faucets with hose spray, anti-syphon type, residential applicationASTM A212.18.1/CSA B125.1
Enameled cast-iron plumbing fixturesASME A112.19.1M/CSA B45.2
Floor drainsASME A112.6.3
Floor-affixed supports for off-the-floor plumbing fixtures for public useASME A112.6.1M
Framing-affixed supports for off-the-floor water closets with concealed tanksASME A112.6.2
Hose connection vacuum breakerASSE 1052
Hot water dispensers, household storage type, electricalASSE 1023
Household disposersASSE 1008
Hydraulic performance for water closets and urinalsASME A112.19.2/CSA B45.1
Individual automatic compensating valves for individual fixture fittingsASME A112.18.1/CSA B125.1
Individual shower control valves anti-scaldASSE 1016/ASME A112.1016/CSA B125.16
Macerating toilet systems and related componentsASME A112.3.4/CSA B45.9
Nonvitreous ceramic plumbing fixturesASME A112.19.2/CSA B45.1
Plastic bathtub unitsCSA B45.5/IAPMO Z124, ASME A112.19.2/CSA B45.1
Plastic lavatoriesCSA B45.5/IAPMO Z124
Plastic shower receptors and shower stallCSA B45.5/IAPMO Z124
Plastic sinksCSA B45.5/IAPMO Z124
Plastic water closet bowls and tanksCSA B45.5/IAPMO Z124
Plumbing fixture fittingsASME A112.18.1/CSA B125.1
Plumbing fixture waste fittingsASME A112.18.2/CSA B125.2, ASTM F409
Porcelain-enameled formed steel plumbing fixturesASME A112.19.1/CSA B45.2
Pressurized flushing devices for plumbing fixturesASSE 1037, CSA B125.3
Specification for copper sheet and strip for building constructionASTM B370
Stainless steel plumbing fixturesASME A112.19.3/CSA B45.4
Suction fittings for use in whirlpool bathtub appliancesASME A112.19.7 /CSA B45.10
Temperature-actuated, flow reduction valves to individual fixture fittingsASSE 1062
Thermoplastic accessible and replaceable plastic tube and tubular fittingsASTM F409
Trench drainsASME A112.6.3
Trim for water closet bowls, tanks and urinalsASME A112.19.5/CSA B45.15
Vacuum breaker wall hydrant-frost-resistant, automatic-draining typeASSE 1019
Vitreous china plumbing fixturesASME A112.19.2/CSA B45.1
Wall-mounted and pedestal-mounted, adjustable and pivoting lavatory and sink
carrier systems
ASME A112.19.12
Water closet flush tank fill valvesASSE 1002, CSA B125.3
Whirlpool bathtub appliancesASME A112.19.7 /CSA B45.10

Plumbing fixtures, other than water closets, shall be provided with approved strainers.

Exception: Hub drains receiving only clear water waste and standpipes shall not require strainers.

Waste fittings shall conform to ASME A112.18.2/CSA B125.2, ASTM F409 or shall be made from pipe and pipe fittings complying with any of the standards indicated in Tables P3002.1(1) and P3002.3.
Plastic tubular fittings shall conform to ASTM F409 as indicated in Table P2701.1.
Carriers for wall-hung water closets shall conform to ASME A112.6.1 or ASME A112.6.2.
Fixture tail pieces shall be not less than 11/2 inches (38 mm) in diameter for sinks, dishwashers, laundry tubs, bathtubs and similar fixtures, and not less than 11/4 inches (32 mm) in diameter for bidets, lavatories and similar fixtures.
Slip joints shall be made with an approved elastomeric gasket and shall be installed only on the trap outlet, trap inlet and within the trap seal. Fixtures with concealed slip-joint connections shall be provided with an access panel or utility space not less than 12 inches (305 mm) in its smallest dimension or other approved arrangement so as to provide access to the slip connections for inspection and repair.

The installation of fixtures shall conform to the following:

  1. Floor-outlet or floor-mounted fixtures shall be secured to the drainage connection and to the floor, where so designed, by screws, bolts, washers, nuts and similar fasteners of copper, copper alloy or other corrosion-resistant material.
  2. Wall-hung fixtures shall be rigidly supported so that strain is not transmitted to the plumbing system.
  3. Where fixtures come in contact with walls and floors, the contact area shall be water tight.
  4. Plumbing fixtures shall be usable.
  5. Water closets, lavatories and bidets. A water closet, lavatory or bidet shall not be set closer than 15 inches (381 mm) from its center to any side wall, partition or vanity or closer than 30 inches (762 mm) center-to-center between adjacent fixtures. There shall be a clearance of not less than 21 inches (533 mm) in front of a water closet, lavatory or bidet to any wall, fixture or door.
  6. The location of piping, fixtures or equipment shall not interfere with the operation of windows or doors.
  7. In flood hazard areas as established by Table R301.2(1), plumbing fixtures shall be located or installed in accordance with Section R322.1.6.
  8. Integral fixture-fitting mounting surfaces on manufactured plumbing fixtures or plumbing fixtures constructed on site, shall meet the design requirements of ASME A112.19.2/CSA B45.1 or ASME A112.19.3/CSA B45.4.
For other than hub drains that receive only clear-water waste and standpipes, a removable strainer or basket shall cover the waste outlet of waste receptors. Waste receptors shall not be installed in concealed spaces. Waste receptors shall not be installed in plenums, attics, crawl spaces or interstitial spaces above ceilings and below floors. Waste receptors shall be readily accessible.
Hub drains shall be in the form of a hub or a pipe that extends not less than 1 inch (25 mm) above a water-impervious floor.
Standpipes shall extend not less than 18 inches (457 mm) and not greater than 42 inches (1067 mm) above the trap weir.
Where a laundry tray waste line connects into a standpipe for an automatic clothes washer drain, the standpipe shall extend not less than 30 inches (762 mm) above the standpipe trap weir and shall extend above the flood level rim of the laundry tray. The outlet of the laundry tray shall not be greater than 30 inches (762 mm) horizontally from the standpipe trap.

Plumbing fixtures that are used for washing or bathing shall not be used to receive the discharge of indirect waste piping.


  1. A kitchen sink trap is acceptable for use as a receptor for a dishwasher.
  2. A laundry tray is acceptable for use as a receptor for a clothes washing machine.
Approved directional-type branch fittings shall be installed in fixture tailpieces receiving the discharge from food-waste disposer units or dishwashers.

Shower compartments shall have not less than 900 square inches (0.6 m2) of interior cross-sectional area. Shower compartments shall be not less than 30 inches (762 mm) in minimum dimension measured from the finished interior dimension of the shower compartment, exclusive of fixture valves, shower heads, soap dishes, and safety grab bars or rails. The minimum required area and dimension shall be measured from the finished interior dimension at a height equal to the top of the threshold and at a point tangent to its centerline and shall be continued to a height of not less than 70 inches (1778 mm) above the shower drain outlet. Hinged shower doors shall open outward. The wall area above builtin tubs having installed shower heads and in shower compartments shall be constructed in accordance with Section R702.4. Such walls shall form a water-tight joint with each other and with either the tub, receptor or shower floor.


  1. Fold-down seats shall be permitted in the shower, provided the required 900-square-inch (0.6 m2) dimension is maintained when the seat is in the folded-up position.
  2. Shower compartments having not less than 25 inches (635 mm) in minimum dimension measured from the finished interior dimension of the compartment provided that the shower compartment has a cross-sectional area of not less than 1,300 square inches (0.838 m2).
The shower compartment access and egress opening shall have a clear and unobstructed finished width of not less than 22 inches (559 mm).
Shower drains shall have an outlet size of not less than 11/2 inches [38 mm] in diameter.
Water supply risers from the shower valve to the shower head outlet, whether exposed or concealed, shall be attached to the structure using support devices designed for use with the specific piping material or fittings anchored with screws.
Individual shower and tub/ shower combination valves shall be equipped with control valves of the pressure-balance, thermostatic-mixing or combination pressure-balance/thermostatic-mixing valve types with a high limit stop in accordance with ASSE 1016/ASME A112.1016/CSA B125.16. The high limit stop shall be set to limit the water temperature to not greater than 120°F (49°C). In-line thermostatic valves shall not be used for compliance with this section.
Hand-held showers shall conform to ASME A112.18.1/CSA B125.1. Hand-held showers shall provide backflow protection in accordance with ASME A112.18.1/CSA B125.1 or shall be protected against backflow by a device complying with ASME A112.18.3.
Where a shower receptor has a finished curb threshold, it shall be not less than 1 inch (25 mm) below the sides and back of the receptor. The curb shall be not less than 2 inches (51 mm) and not more than 9 inches (229 mm) deep when measured from the top of the curb to the top of the drain. The finished floor shall slope uniformly toward the drain not less than 1/4 unit vertical in 12 units horizontal (2-percent slope) nor more than 1/2 unit vertical per 12 units horizontal (4-percent slope) and floor drains shall be flanged to provide a water-tight joint in the floor.

The adjoining walls and floor framing enclosing on-site built-up shower receptors shall be lined with one of the following materials:

  1. Sheet lead.
  2. Sheet copper.
  3. Plastic liner material that complies with ASTM D4068 or ASTM D4551.
  4. Hot mopping in accordance with Section P2709.2.3.
  5. Sheet-applied load-bearing, bonded waterproof membranes that comply with ANSI A118.10.

The lining material shall extend not less than 2 inches (51 mm) beyond or around the rough jambs and not less than 2 inches (51 mm) above finished thresholds. Sheet-applied load bearing, bonded waterproof membranes shall be applied in accordance with the manufacturer’s instructions.


  1. Floor surfaces under shower heads provided for rinsing laid directly on the ground are not required to comply with this section.
  2. Where a sheet-applied, load-bearing, bonded, waterproof membrane is installed as the shower lining, the membrane shall not be required to be recessed.
  3. Shower compartments where the finished shower drain is depressed a minimum of 2 inches (51 mm) below the surrounding finished floor on the first floor level and the shower recess is poured integrally with the adjoining floor.
Plasticized polyvinyl chloride (PVC) sheet shall meet the requirements of ASTM D4551. Sheets shall be joined by solvent welding in accordance with the manufacturer’s instructions.
Nonplasticized chlorinated polyethylene sheet shall meet the requirements of ASTM D4068. The liner shall be joined in accordance with the manufacturer’s instructions.
Shower receptors lined by hot mopping shall be built-up with not less than three layers of standard grade Type 15 asphalt-impregnated roofing felt. The bottom layer shall be fitted to the formed subbase and each succeeding layer thoroughly hot-mopped to that below. Corners shall be carefully fitted and shall be made strong and water tight by folding or lapping, and each corner shall be reinforced with suitable webbing hot-mopped in place. Folds, laps and reinforcing webbing shall extend not less than 4 inches (102 mm) in all directions from the corner and webbing shall be of approved type and mesh, producing a tensile strength of not less than 50 pounds per inch (893 kg/m) in either direction.
Liquid-type, trowelapplied, load-bearing, bonded waterproof materials shall meet the requirements of ANSI A118.10 and shall be applied in accordance with the manufacturer’s instructions.
Lining materials shall be sloped onefourth unit vertical in 12 units horizontal (2-percent slope) to weep holes in the subdrain by means of a smooth, solidly formed subbase, shall be properly recessed and fastened to approved backing so as not to occupy the space required for the wall covering, and shall not be nailed or perforated at any point less than 1 inch (25.4 mm) above the finished threshold.
Lead and copper linings shall be insulated from conducting substances other than the connecting drain by 15-pound (6.80 kg) asphalt felt or its equivalent. Sheet lead liners shall weigh not less than 4 pounds per square foot (19.5 kg/m2). Sheet copper liners shall weigh not less than 12 ounces per square foot (3.7 kg/m2). Joints in lead and copper pans or liners shall be burned or silver brazed, respectively. Joints in plastic liner materials shall be joined in accordance with the manufacturer’s instructions.
An approved flanged drain shall be installed with shower subpans or linings. The flange shall be placed flush with the subbase and be equipped with a clamping ring or other device to make a water-tight connection between the lining and the drain. The flange shall have weep holes into the drain.
Walls in shower compartments and walls above bathtubs that have a wall-mounted showerhead shall be finished in accordance withSection R307.2.
Lavatories shall conform to ASME A112.19.1/CSA B45.2, ASME A112.19.2/CSA B45.1, ASME A112.19.3/CSA B45.4 or CSA B45.5/IAPMO Z124.
Cultured marble vanity tops with an integral lavatory shall conform to CSA B45.5/IAPMO Z124.
Lavatories shall have waste outlets not less than 11/4 inch (32 mm) in diameter. A strainer, pop-up stopper, crossbar or other device shall be provided to restrict the clear opening of the waste outlet.
Movable lavatory systems shall comply with ASME A112.19.12.
Water closets shall conform to the water consumption requirements of Section P2903.2 and shall conform to ASME A112.19.2/CSA B45.1, ASME A112.19.3/ CSA B45.4 or CSA B45.5/IAPMO Z124. Water closets shall conform to the hydraulic performance requirements of ASME A112.19.2/CSA B45.1. Water closet tanks shall conform to ASME A112.19.2/CSA B45.1, ASME A112.19.3/CSA B45.4 or CSA B45.5/IAPMO Z124. Water closets that have an invisible seal and unventilated space or walls that are not thoroughly washed at each discharge shall be prohibited. Water closets that allow backflow of the contents of the bowl into the flush tank shall be prohibited. Water closets equipped with a dual flushing device shall comply with ASME A112.19.14.
Water closets shall be provided with a flush tank, flushometer tank or flushometer valve designed and installed to supply water in sufficient quantity and flow to flush the contents of the fixture, to cleanse the fixture and refill the fixture trap in accordance with ASME A112.19.2/CSA B45.1.
An adequate quantity of water shall be provided to flush and clean the fixture served. The water supply to flushing devices equipped for manual flushing shall be controlled by a float valve or other automatic device designed to refill the tank after each discharge and to completely shut off the water flow to the tank when the tank is filled to operational capacity. Provision shall be made to automatically supply water to the fixture so as to refill the trap after each flushing.
Flush valve seats in tanks for flushing water closets shall be not less than 1 inch (25 mm) above the flood-level rim of the bowl connected thereto, except an approved water closet and flush tank combination designed so that when the tank is flushed and the fixture is clogged or partially clogged, the flush valve will close tightly so that water will not spill continuously over the rim of the bowl or backflow from the bowl to the tank.
Flush tanks shall be provided with overflows discharging to the water closet connected thereto and such overflow shall be of sufficient size to prevent flooding the tank at the maximum rate at which the tanks are supplied with water according to the manufacturer’s design conditions.
Parts in a flush tank shall be accessible for repair and replacement.
Water closets shall be equipped with seats of smooth, nonabsorbent material and shall be properly sized for the water closet bowl type.
Sheet copper used for flush tank linings shall have a weight of not less than 10 ounces per square foot (3 kg/m2).
Electro-hydraulic water closets shall conform to ASME A112.19.2/CSA B45.1.
Bathtubs shall be equipped with a waste outlet and an overflow outlet. The outlets shall be connected to waste tubing or piping not less than 11/2 inches (38 mm) in diameter. The waste outlet shall be equipped with a water-tight stopper.
Doors within a bathtub enclosure shall conform to ASME A112.19.15.
Hot water supplied to bathtubs and whirlpool bathtubs shall be limited to a temperature of not greater than 120°F (49°C) by a watertemperature limiting device that conforms to ASSE 1070 or CSA B125.3, except where such protection is otherwise provided by a combination tub/shower valve in accordance with Section P2708.4.
Sinks shall be provided with waste outlets not less than 11/2 inches (38 mm) in diameter. A strainer, crossbar or other device shall be provided to restrict the clear opening of the waste outlet.
Movable sink systems shall comply with ASME A112.19.12.
Each compartment of a laundry tub shall be provided with a waste outlet not less than 11/2 inches (38 mm) in diameter. A strainer or crossbar shall restrict the clear opening of the waste outlet.
Food-waste disposers shall be connected to a drain of not less than 11/2 inches (38 mm) in diameter.
A sink equipped with a food-waste disposer shall be provided with a faucet.
The water supply to a dishwasher shall be protected against backflow by an air gap complying with ASME A112.1.3 or A112.1.2 that is installed integrally within the machine or a backflow preventer in accordance with Section P2902.
The combined discharge from a dishwasher and a one- or two-compartment sink, with or without a food-waste disposer, shall be served by a trap of not less than 11/2 inches (38 mm) in outside diameter. The dishwasher discharge pipe or tubing shall rise to the underside of the counter and be fastened or otherwise held in that position before connecting to the head of the food-waste disposer or to a wye fitting in the sink tailpiece.
The discharge from a clothes washing machine shall be through an air break.
Floor drains shall have waste outlets not less than 2 inches (51 mm) in diameter and a removable strainer. Floor drains shall be constructed so that the drain can be cleaned. Access shall be provided to the drain inlet. Floor drains shall not be located under or have their access restricted by permanently installed appliances.
Access shall be provided to circulation pumps in accordance with the fixture or pump manufacturer's installation instructions. Where the manufacturer’s instructions do not specify the location and minimum size of field-fabricated access openings, an opening of not less than 12-inches by 12-inches (305 mm by 305 mm) shall be installed for access to the circulation pump. Where pumps are located more than 2 feet (610 mm) from the access opening, an opening of not less than 18 inches by 18 inches (457 mm by 457 mm) shall be installed. A door or panel shall be permitted to close the opening. The access opening shall be unobstructed and be of the size necessary to permit the removal and replacement of the circulation pump.
The circulation pump shall be accessibly located above the crown weir of the trap. The pump drain line shall be properly graded to ensure minimum water retention in the volute after fixture use. The circulation piping shall be installed to be self-draining.
Leak testing and pump operation shall be performed in accordance with the manufacturer’s instructions.
The product shall be installed in accordance with the manufacturer’s instructions.
The bidet shall be equipped with either an air-gap-type or vacuum-breaker-type fixture supply fitting.
The discharge water temperature from a bidet fitting shall be limited to not greater than 110°F (43°C) by a water-temperature-limiting device conforming to ASSE 1070 or CSA B125.3.
Fixture supply valves and faucets shall comply with ASME A112.18.1/CSA B125.1 as indicated in Table P2701.1. Faucets and fixture fittings that supply drinking water for human ingestion shall conform to the requirements of NSF 61, Section 9. Flexible water connectors shall conform to the requirements of Section P2906.7.

Fixture fittings supplied with both hot and cold water shall be installed and adjusted so that the lefthand side of the water temperature control represents the flow of hot water when facing the outlet.

Exception: Shower and tub/shower mixing valves conforming to ASSE 1016/ASME A112.1016/CSA B125.16, where the water temperature control corresponds to the markings on the device.

Faucets and fixture fittings with hose-connected outlets shall conform to ASME A112.18.3 or ASME A112.18.1/CSA B125.1.
Individual pressure-balancing inline valves for individual fixture fittings shall comply with ASSE 1066. Such valves shall be installed in an accessible location and shall not be used as a substitute for the balanced pressure, thermostatic or combination shower valves required in Section P2708.4.
Personal hygiene devices integral to water closets or water closet seats shall conform to ASME A112.4.2.
Macerating toilet systems shall be installed in accordance with manufacturer’s instructions.
The size of the drain from the macerating toilet system shall be not less than 3/4 inch (19 mm) in diameter.
Temperature-actuated mixing valves, which are installed to reduce water temperatures to defined limits, shall comply with ASSE 1017. Such valves shall be installed at the hot water source.
Temperature-actuated, flow-reduction devices, where installed for individual fixture fittings, shall conform to ASSE 1062. Such valves shall not be used as a substitute for the balanced pressure, thermostatic or combination shower valves required for showers in Section P2708.4.
Materials, design, construction and performance of nonliquid saturated treatment systems shall comply with NSF 41.
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