UPC Section 609 sets how potable water piping is installed, supported, protected, and tested. New water lines must be supported at set spacing and shielded where they could be damaged. Before the system is covered, it must pass a pressure test. The plumber holds the pipe at working pressure with water, or at 50 psi with air, for 15 minutes with no leaks.
The Uniform Plumbing Code is published and copyrighted by IAPMO. This page explains the section in our own words with a short excerpt only. Read the full official text at the source.
The pipes that bring drinking water to your fixtures run under pressure all day, every day. A weak joint or a poorly supported line can leak for years behind a wall or under a slab. UPC Section 609 sets how that water piping is put in, held up, protected, and tested. The goal is a system that stays tight and clean for the life of the home.
What this section covers
Section 609 is titled Installation, Testing, Unions, and Location:
609.0 Installation, Testing, Unions, and Location
The section pulls together four jobs. The pipe must be an approved material, then installed and joined the right way. It must be supported so it does not sag. It must be placed in a safe location and protected where it could be hit or crushed. And the finished system must pass a pressure test before it is covered.
Support and protection
Water pipe cannot just be laid loose. It has to be held up at regular spacing so it does not sag, rub, or pull on its joints. Where a line runs through a stud or a plate, it needs a shield so a nail or screw cannot pierce it later. Pipe run under a slab or in the ground gets extra care so the soil, concrete, and any settling do not crush or wear it. Good support is also why a house does not bang and rattle every time the water turns on.
Unions and shutoffs
The code calls for a union or a similar fitting near equipment that will need service. A union lets a plumber unbolt and pull a water heater or a treatment tank without cutting the pipe. The rule places that union close to the equipment, within about 12 inches, so the connection is easy to reach when the unit is replaced.
The pressure test
Before the walls close, the new water system gets a pressure test to prove it is tight. The plumber can use a water test at a pressure at least equal to the working pressure the system will see in use. Or the plumber can use an air test at not less than 50 psi. Either way, the pipe must hold that pressure with no leaks for at least 15 minutes while the inspector checks. A pressure drop points to a joint that has to be fixed and retested.
What this means for you
Solid support and a clean pressure test are what keep water lines from leaking down the road. If you are repiping or adding a line, this inspection happens before the drywall goes back up. It is one more reason to hire a licensed plumber who tests the work instead of guessing. To learn what normal home pressure looks like, see what home water pressure should be. For support spacing, see UPC pipe support spacing. And to spot a hidden leak on your own meter, see how to do a water meter leak test.
Full text and source
UPC Section 609 is part of the Uniform Plumbing Code. IAPMO publishes it and holds the copyright, so only the section heading and short notes are shown here. The test values above are described in plain terms, not quoted. 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.
Keep Reading
- UPC 606: Where Shutoff Valves Are Required
- UPC Section 720: The Required Gap Between Water and Sewer Lines
- UPC 1003: Which Fixture Traps Are Allowed (and Banned)
- UPC 1007: Trap Seal Protection for Floor Drains
- What should my home water pressure be?
- How do I use my water meter to check for a leak?
- What causes pinhole leaks in copper pipes?