Yes. New water piping must pass a pressure test held for at least 15 minutes, and the IPC requires new potable systems to be flushed and disinfected before use, either by the local method or by the chlorine procedure it describes. In Phoenix, water piping also needs a rough-in inspection before it is concealed.
What pressure test does new water piping need?
A tightness test. IPC Section 312.6 says: "Upon completion of a section of or the entire water supply system, the system, or portion completed, shall be tested and proved tight under a water pressure not less than the working pressure of the system; or, for piping systems other than plastic, by an air test of not less than 50 psi." The pressure "shall be held for not less than 15 minutes," and "The water utilized for tests shall be obtained from a potable source of supply." Plastic pipe such as PEX or CPVC is tested with water; the air option is for other materials. The permit holder arranges the test, gives the code official advance notice, and supplies the equipment, per Section 312.1.
When does the inspector look at it?
Before the pipe is covered. Phoenix's administrative provisions say: "A rough-in or underground inspection is required for all sewer, drainage and vent piping, and for all water and gas distribution systems prior to their being buried or concealed." A final inspection follows "when all fixtures are set and operating or ready to operate pending final utility connection," and tests are "performed as required by the applicable Plumbing Code." Expect the water lines to be tested and left open for that rough-in inspection, before drywall, ceiling tile or slab covers them. Our guide to the plumbing top-out inspection explains that stage, and what happens when a commercial plumbing inspection fails covers the retest.
Does the water system have to be disinfected?
Yes. IPC Section 610.1 says: "New potable water systems shall be purged of deleterious matter and disinfected prior to utilization." Whose method applies comes first: "The method to be followed shall be that prescribed by the health authority or water purveyor having jurisdiction or, in the absence of a prescribed method, the procedure described in either AWWA C651 or AWWA C652, or as described in this section." The requirement also applies to "on-site" or "in-plant" fabrication or a modular portion of a system.
What are the disinfection steps?
The section's own procedure runs like this:
- 1Flush. "The pipe system shall be flushed with clean, potable water until dirty water does not appear at the points of outlet."
- 2Fill with chlorine solution at one of two strengths: not less than 50 parts per million, valved off and left to stand for 24 hours, or not less than 200 parts per million and left for 3 hours.
- 3Flush again. After the standing time, the system "shall be flushed with clean potable water until the chlorine is purged from the system."
- 4Repeat if needed. "The procedure shall be repeated where shown by a bacteriological examination that contamination remains present in the system."
Strongly chlorinated water has to go somewhere when it is flushed out, so ask the local water provider where it may be discharged before anyone opens a hose.
What does this mean for a tenant buildout or new building?
Plan the schedule. A line that passes pressure testing still has to be flushed and treated before the sinks, ice machines and drinking fountains go into service, and a repeat disinfection takes more days. If a restaurant's opening date depends on the water being cleared, ask the plumber when the test and the disinfection will be done, and what the local water provider or health authority prescribes. Related: whether you need a permit for commercial tenant plumbing work and when concealed plumbing needs to stay open for inspection.
Codes and local procedures vary, and the building official's approved plans control. HQ is licensed and insured and gives free estimates, so a new buildout's water piping can be priced with the testing and inspections included.