General Plumbing Requirements

This chapter outlines general plumbing requirements, covering water supply, sewage disposal, structural protection during installation, trenching, pipe support, waterproofing, workmanship, and material identification.

P2601 — General

P2601.1 Scope. The provisions of this chapter shall govern the installation of plumbing not specifically covered in other chapters applicable to plumbing systems. The installation of plumbing, appliances, equipment and systems not addressed by this code shall comply with the applicable provisions of the International Plumbing Code.

P2601.2 Connection. Plumbing fixtures, drains and appliances used to receive or discharge liquid wastes or sewage shall be connected to the sanitary drainage system of the building or premises in accordance with the requirements of this code. This section shall not be construed to prevent indirect waste systems.

P2601.3 Flood hazard area. In areas prone to flooding as established by Table R301.2(1), plumbing fixtures, drains, and appliances shall be located or installed in accordance with Section R322.1.6.

P2602 — Individual Water Supply and Sewage Disposal

P2602.1 General. The water-distribution and drainage system of any building or premises where plumbing fixtures are installed shall be connected to a public water supply or sewer system, respectively, if available. When either a public water-supply or sewer system, or both, are not available, or connection to them is not feasible, an individual water supply or individual (private) sewage-disposal system, or both, shall be provided.

P2602.2 Flood-resistant installation. In areas prone to flooding as established by Table R301.2(1):

Water supply systems shall be designed and constructed to prevent infiltration of floodwaters.
Pipes for sewage disposal systems shall be designed and constructed to prevent infiltration of floodwaters into the systems and discharges from the systems into floodwaters.

Worked example

Scenario: An architect is designing a new single-family home in a rural area where municipal water and sewer lines are not extended to the property.

Explanation: According to P2602.1, since public water and sewer systems are unavailable, the design must incorporate an approved individual well for water supply and a septic system for sewage disposal, rather than connecting to non-existent public utilities.

P2603 — Structural and Piping Protection

P2603.1 General. In the process of installing or repairing any part of a plumbing and drainage installation, the finished floors, walls, ceilings, tile work or any other part ofthe building or premises that must be changed or replaced shall be left in a safe structural condition in accordance with the requirements of the building portion of this code.

P2603.2 Drilling and notching. Wood-framed structural members shall not be drilled, notched or altered in any manner except as provided in Sections R502.8, R602.5, R602.6, R802.7 and R802.7.1. Holes in load-bearing members of cold-formed steel light-frame construction shall be permitted only in accordance with Sections R505.3.5, R603.2.5 and R804. 2.5. In accordance with the provisions in Sections R505.3.5, R603.3.4 and R804.3.4, cutting and notching of flanges and lips of load-bearing members of cold-formed steel light-frame construction shall not be permitted. Structural insulated panels (SIPs) shall be drilled and notched or altered in accordance with the provisions of Section R613. 7.

P2603.2.1 Protection against physical damage. In concealed locations, where piping, other than cast-iron or galvanized steel, is installed through holes or notches in studs, joists, rafters or similar members less than 1½ inches (38 mm) from the nearest edge of the member, the pipe shall be protected by steel shield plates. Such shield plates shall have a thickness of not less than 0.0575 inch (1.463 mm) (No. 16 Gage). Such plates shall cover the area of the pipe where the member is notched or bored, and shall extend a minimum of 2 inches (51 mm) above sole plates and below top plates.

P2603.2.1 Protection against physical damage. In concealed locations, where piping, other than cast-iron or galvanized steel, is installed through holes or notches in studs, joists, rafters or similar members less than 1½ inches (38 mm) from the nearest edge of the member, the pipe shall be protected by steel shield plates. Such shield plates shall have a thickness of not less than 0.0575 inch (1.463 mm) (No. 16 Gage). Such plates shall cover the area of the pipe where the member is notched or bored, and shall extend a minimum of 2 inches (51 mm) above sole plates and below top plates.

P2603.3 Breakage and corrosion. Pipes passing through or under walls shall be protected from breakage. Pipes passing through concrete or cinder walls and floors, cold-formed steel framing or other corrosive material shall be protected against external corrosion by a protective sheathing or wrapping or other means that will withstand any reaction from lime and acid of concrete, cinder or other corrosive material. Sheathing or wrapping shall allow for movement including expansion and contraction of piping. Minimum wall thickness of material shall be 0.025 inch (0.64 mm).

P2603.4 Sleeves. Annular spaces between sleeves and pipes shall be filled or tightly caulked as approved by the building official. Annular spaces between sleeves and pipes in fire-rated assemblies shall be filled or tightly caulked in accordance with the building portion of this code.

P2603.5 Pipes through footings or foundation walls. Any pipe that passes under a footing or through a foundation wall shall be provided with a relieving arch; or there shall be built into the masonry wall a pipe sleeve two pipe sizes greater than the pipe passing through.

P2603.6 Freezing. In localities having a winter design temperature of32°P (O°C) or lower as shown in Table R301.2(1) of this code, a water, soil or waste pipe shall not be installed outside ofa building, in exterior walls, in attics or crawl spaces, or in any other place subjected to freezing temperature unless adequate provision is made to protect it from freezing by insulation or heat or both. Water service pipe shall be installed not less than 12 inches (305 mm) deep and not less than 6 inches (152 mm) below the frost line.

P2603.6.1 Sewer depth. BUilding sewers that connect to private sewage disposal systems shall be a minimum of [NUMBER] inches (mm) below finished grade at the point of septic tank connection. BUildingsewers shall be a minimum of [NUMBER] inches (mm) below grade.

P2603.6.1 Sewer depth. BUilding sewers that connect to private sewage disposal systems shall be a minimum of [NUMBER] inches (mm) below finished grade at the point of septic tank connection. BUildingsewers shall be a minimum of [NUMBER] inches (mm) below grade.

Worked example

Scenario: During a bathroom renovation, a plumber needs to run new drain lines through an existing load-bearing wall.

Explanation: P2603.1 mandates that any modifications to the structural wall (such as notching or boring for pipes) must be done in a manner that maintains the wall's safe structural condition, adhering to the building code's requirements for structural integrity.

P2604 — Trenching and Backfilling

P2604.1 Trenching and bedding. Where trenches are excavated such that the bottom of the trench forms the bed for the pipe, solid and continuous load-bearing support shall be provided betweenjoints. Where over-excavated, the trench shall be backfilled to the proper grade with compacted earth, sand, fine gravel or similar granular material. Piping shall not be supported on rocks or blocks at any point. Rocky or unstable soil shall be over-excavated by two or more pipe diameters and brought to the proper grade with suitable compacted granular material.

P2604.2 Common trench. See Section P2905.4.2.

P2604.3 Backfilling. Backfill shall be free from discarded construction material and debris. Backfill shall be free from rocks, broken concrete and frozen chunks until the pipe is covered by at least 12 inches (305 mm) of tamped earth. Backfill shall be placed evenly on both sides of the pipe and tamped to retain proper alignment. Loose earth shall be carefully placed in the trench in 6-inch (152 mm) layers and tamped in place.

P2604.4 Protection of footings. Trenching installed parallel to footings shall not extend below the 45-degree (0.79 rad) bearing plane ofthe bottom edge ofa wall or footing (see Figure P2604.4).

FIGURE P2604.4 PIPE LOCATION WITH RESPECT TO FOOTINGS

Figure from IRC 2009 Section P2604.

Worked example

Scenario: A contractor is installing a new underground sewer line from a house to a septic tank, requiring a trench excavation.

Explanation: P2604.1 requires that the bottom of the trench provides solid and continuous support for the pipe between joints. If the trench is over-excavated, it must be properly backfilled with compacted earth, sand, or gravel to ensure adequate pipe bedding and support.

P2605 — Support

P2605.1 General. Piping shall be supported in accordance with the following:

Piping shall be supported to ensure alignment and prevent sagging, and allow movement associated with the expansion and contraction of the piping system.
Piping in the ground shall be laid on a firm bed for its entire length, except where support is otherwise provided.
Hangers and anchors shall be of sufficient strength to maintain their proportional share of the weight of pipe and contents and of sufficient width to prevent distortion to the pipe. Hangers and strapping shall be of approved material that will not promote galvanic action. Rigid support sway bracing shall be provided at changes in direction greater than 45 degrees (0.79 rad) for pipe sizes 4 inches (102 mm) and larger.
Piping shall be supported at distances not to exceed those indicated in Table P2605.1.

P2606 — Waterproofing of Openings

P2606.1 General. Roof and exterior wall penetrations shall be made water tight. Joints at the roof, around vent pipes, shall be made water tight by the use of lead, copper or galvanized iron flashings or an approved elastomeric material. Counterflashing shall not restrict the required internal cross-sectional area of any vent.

Worked example

Scenario: A vent pipe from a plumbing system penetrates the roof of a commercial building.

Explanation: P2606.1 requires that the penetration at the roof must be made watertight. This will typically involve installing a flashing system, such as a lead or galvanized iron flashing and counterflashing, to prevent water intrusion while ensuring the counterflashing does not impede the vent pipe's internal cross-sectional area.

P2607 — Workmanship

P2607.1 General. Valves, pipes and fittings shall be installed in correct relationship to the direction of the flow. Burred ends shall be reamed to the full bore of the pipe.

Worked example

Scenario: A plumber is installing new copper piping for a water distribution system.

Explanation: According to P2607.1, the plumber must ensure that all valves are installed with the correct flow direction. After cutting the pipes, any burred ends must be reamed to the full bore of the pipe to prevent flow restriction and reduce turbulence.

P2608 — Materials Evaluation and Listing

P2608.1 Identification. Each length of pipe and each pipe fitting, trap, fixture, material and device used in a plumbing system shall bear the identification of the manufacturer.

P2608.2 Installation of materials. All materials used shall be installed in strict accordance with the standards under which the materials are accepted and approved. In the absence of such installation procedures, the manufacturer's installation instructions shall be followed. Where the requirements of referenced standards or manufacturer's installation instructions do not conform to the minimum provisions of this code, the provisions of this code shall apply.

P2608.3 Plastic pipe, fittings and components. All plastic pipe, fittings and components shall be third-party certified as conforming to NSF 14.

P2608.4 Third-party testing and certification. All plumbing products and materials shall comply with the referenced standards, specifications and performance criteria of this code and shall be identified in accordance with Section P2608.1. Where required by Table P2608.4, plumbing products and materials shall either be tested by an approvedthird-party testing agency or certified by an approved third-party certification agency.

P2608.5 Water supply systems. Water service pipes, water distribution pipes and the necessary connecting pipes, fittings, control valves, faucets and all appurtenances used to dispense water intended for human ingestion shall be evaluated and listed as conforming to the requirements of NSF 61.

A table appears here in the adopted code. Refer to the official source for the full table.

Frequently asked questions

When is it permissible to use an individual water supply or sewage disposal system?

Individual water supply or sewage disposal systems are allowed only when a public water supply or sewer system, or both, are not available or connection to them is not feasible.

What precautions must be taken for structural elements during plumbing installation?

During plumbing installation or repair, finished floors, walls, ceilings, tile work, or any other affected part of the building must be left in a safe structural condition consistent with code requirements.

What are the requirements for supporting pipes and preventing leaks at penetrations?

Piping must be supported as specified by code, and all roof and exterior wall penetrations for plumbing must be made watertight using approved flashing materials like lead, copper, galvanized iron, or elastomeric materials.