Section 312.1/Testing of Plumbing Systems
IPC 312 covers required pressure and leak tests for drainage, water supply, and storm drainage piping before concealment.
The drainage, waste, and vent (DWV) system must be tested with either a water test or an air test before concealment. The water test requires filling the system with water to the level of the highest opening and maintaining the water level for 15 minutes. The air test requires pressurizing the system to 5 psi and holding for 15 minutes with no pressure drop. The water supply system must be tested at the working pressure or a minimum of 40 psi, whichever is greater, for a period sufficient to determine if leaks exist. Storm drainage must be tested similarly to the DWV system.
Why this section exists
A leak in a concealed plumbing pipe can cause extensive water damage, mold growth, and structural deterioration before it is discovered. Testing the system before it is covered by finishes identifies leaks while repairs are simple and inexpensive. Once walls, ceilings, and floors are finished, finding and repairing a leak requires demolition and reconstruction of the finishes. The test duration and pressure ensure that even small leaks are detected.
What plan reviewers look for
Plan reviewers check the plumbing specifications for the testing requirements. While the testing itself is a construction activity, the specifications must reference IPC Section 312 and note the test method, pressure, and duration for each piping system. Reviewers also verify that the inspection schedule allows for testing before concealment.
Common violations
Related IPC requirements
Section 312.2 covers DWV system testing specifics. Section 312.5 covers water supply testing. Section 604 covers water supply system design that determines the test pressure. Section 107 covers the inspection requirements that coordinate with testing.