IAPMO Releases 2027 Uniform Plumbing And Mechanical Codes

ONTARIO, CA — IAPMO® has published the 2027 editions of the Uniform Plumbing Code® (UPC) and Uniform Mechanical Code® (UMC), completing the latest three-year American National Standards Institute (ANSI)-accredited consensus development cycle and delivering a wide range of updates affecting plumbing, hydronic, HVAC and mechanical contractors.

The new editions are now available in hardcopy and digital formats, giving contractors, inspectors and engineers field access to the latest requirements from any mobile device or computer.

New Plumbing Code Expands Water Heater and Water Safety Requirements

Among the most significant updates in the 2027 UPC are new provisions addressing dual-purpose and instantaneous (tankless) water heater sizing, flow-through expansion tanks and updated gray water system requirements.

For plumbing contractors, the revisions provide clearer guidance on specifying and installing modern water heating systems, particularly as demand for tankless systems and water reuse applications continues to grow.

Additional updates include new requirements for adult changing stations, pitless adapters, well caps, vacuum testing of drainage and vent systems, and rehabilitation of existing building sewer and storm sewer piping.

The updated code also expands water safety provisions with revised Appendix N for building water management planning and monitoring to reduce Legionella growth and scalding risks, along with new Appendix Q for safely operating, shutting down and reopening building water systems.

Hydronic And Closed-Loop System Guidance Sees Major Expansion

The 2027 UMC includes important new resources for hydronic professionals, including Appendix K, which provides recommended configurations for maintaining heat transfer fluid quality in closed-loop hydronic systems.

That addition gives hydronic contractors more structured guidance for fluid maintenance, system efficiency and long-term equipment protection.

The UMC also expands district energy system requirements beyond Ambient Temperature Loop (ATL) systems, reflecting broader industry adoption of shared thermal energy networks.

Other new plumbing and mechanical crossover provisions include hydrogen fuel gas piping system guidance in both codes, reflecting growing interest in alternative fuel applications.

Mechanical Code Adds New Ventilation And Refrigeration Requirements

Mechanical contractors will also see new exhaust ventilation requirements for auto repair garages, indoor DC fast-charging EV spaces and LP-Gas facilities.

Additional changes include new laboratory exhaust system requirements, radioactive material exhaust systems, grease duct leakage testing and updated refrigeration rules related to charge limits, machinery rooms and refrigerant piping.

These revisions are expected to affect both design and installation practices across commercial mechanical projects.

Training Resources Support Faster Code Adoption

To help contractors and inspectors adapt to the changes, IAPMO has also released the 2027 Uniform Codes Illustrated Training Manuals (ITM) and Guide to Important Code Changes (GTICC), providing practical instruction and visual explanations of new code requirements.

The Uniform Codes are developed through IAPMO’s ANSI-accredited consensus process, which brings together contractors, inspectors, engineers, manufacturers and other industry stakeholders to shape the next generation of plumbing and mechanical standards.

Introduced in 1928 and formally published in 1945, the UPC continues to serve as one of the industry’s most widely adopted plumbing codes, while the UMC remains a key framework for HVAC, combustion, refrigeration and exhaust systems.

The 2027 UPC and 2027 UMC, as well as the corresponding ITM and GTICC, may be purchased through the IAPMO bookstore at: iapmostore.org.