IAPMO
Uniform Plumbing Code
Published by International Association of Plumbing and Mechanical Officials (IAPMO) · written for United States
iapmo.org · checked 2026-09-23
Citing it here is not conformity with it, and this site holds no copy of its text.
- 3Calculators cite it
- 1Sections cited
- 3Editions listed
What it governs
The other United States plumbing code, published by IAPMO and adopted in place of the IPC across much of the west: the same subjects, sized and detailed differently. The difference matters in practice rather than in principle.
Fixture unit values, permitted materials and venting arrangements diverge between the two, so a system sized under one and inspected under the other can fail on arrangement while being correct on quantity. Which of the two applies is a question for the jurisdiction, not for the designer, and it is the single most common reason a plumbing calculation from the internet does not match a local inspector's expectation.
Its materials provisions are the other common divergence: a pipe material accepted under one code is not automatically accepted under the other, and that is a procurement question rather than a design one. Where a jurisdiction has adopted neither cleanly — a state code amending one of them heavily — the amendments govern, and the base document becomes a starting point rather than the answer.
Obtained from International Association of Plumbing and Mechanical Officials. What IAPMO publishes
Editions
Published: 2024, 2021, 2018. A new edition every three years.
Adoption is not verified for your jurisdiction. A model document binds only where an authority adopted it, usually some editions behind and amended locally. Citing a clause is not conformance. No part of the text is reproduced here.