UPC 712: Testing Drain, Waste and Vent Piping

Section 712 is titled Testing Procedures for Drain, Waste, and Vent Piping:

712.0 Testing Procedures for Drain, Waste, and Vent Piping

The test happens after the rough piping is in but before it is covered. The installer must select a test method that meets the adopted code, local amendments and the pipe manufacturer's instructions. A reference to a water test or an air test is not permission to use either method on every material. Passing a test checks for leakage under those test conditions; it does not guarantee that the system will never leak.

Charlotte Pipe recommends a water, or hydrostatic, test for its completed plastic piping installations. Its DWV instructions describe a 10-foot head of water: the height of the water column creates the test pressure. That manufacturer example does not establish the requirements for every system. Before testing, the installer must confirm the applicable method, water head, duration and inspection requirements with the adopted code, local authority and manufacturer. Concealed work stays uncovered until the required test is made and approved.

Do not treat compressed-air testing as a routine option for plastic DWV pipe. Charlotte Pipe's Plastics Technical Manual explicitly prohibits testing ABS, CPVC or PVC pipe or fittings with compressed air or gas, including air-over-water boosters, because explosive failures can cause severe injury or death. A generic code reference or a low test pressure does not override that prohibition. For other materials, an air test must be permitted by the applicable code, local authority and manufacturer. The installer must establish the permitted method before testing; this page does not approve an air or vacuum procedure for a particular installation.

The line that carries waste from the house to the city main gets its own check. Section 723 covers the Building Sewer Test. That test makes sure the buried sewer lateral is sealed and holds water before it is backfilled.

If you are building, remodeling, or moving drains, plan for this inspection. The pipe cannot be covered until it passes. A failed test means finding the leak and testing again, which adds time. This is also why a licensed plumber pressure-tests work rather than eyeballing it. For the permit steps, see new construction plumbing permits in Phoenix. Testing pairs with correct grade and fittings, so see drain pipe slope and changes of direction. To learn how leaks are traced later, see how plumbers find hidden leaks.

UPC Section 712 is part of the Uniform Plumbing Code. IAPMO publishes it and holds the copyright, so only the section headings and short notes are shown here. The water-head example above is a manufacturer recommendation, not a substitute for the adopted code's testing requirements or local approval. Phoenix enforces the 2024 UPC with local amendments. Read the section on the UPC viewer at UpCodes, review the official code at IAPMO, or confirm local amendments with the City of Phoenix Planning & Development Department at phoenix.gov/pdd.