IAPMO has published the 2027 editions of the Uniform Plumbing Code (UPC) and Uniform Mechanical Code (UMC) in both hardcopy and electronic versions, completing a three-year consensus development cycle accredited by the American National Standards Institute (ANSI).

Significant changes to the UPC include:

• New provisions for adult changing stations
• New provisions for laminar flow faucets in healthcare facilities
• New provisions for sizing of dual-purpose and instantaneous (tankless) water heaters
• New provisions for flow-through expansion tanks in water supply and distribution systems
• New provisions for pitless adapters, pitless units, and well caps
• New provisions for vacuum testing of drainage and vent systems
• New provisions for rehabilitation of existing building sewer and storm sewer piping
• Updated gray water system provisions addressing soil infiltration rates for nonpotable applications
• Updates to Appendix N addressing building water management planning and monitoring to reduce Legionella and scalding risks in plumbing systems
• New Appendix Q providing requirements for the safe operation, closure, and reopening of building water systems
• New Appendix U providing recommended practice for hydrogen fuel gas piping systems
• New Appendix V providing minimum requirements for onsite wastewater treatment systems for direct potable water reuse

Significant changes to the UMC include:

• New exhaust ventilation requirements for auto repair garages, indoor DC fast‑charging EV spaces, and LP‑Gas facilities
• Updated certification pathways for qualified personnel performing ventilation system testing, adjusting, and balancing (TAB) and duct leakage testing
• New provisions for laboratory exhaust systems
• New provisions for exhaust systems conveying radioactive materials
• New prescriptive requirements for grease duct leakage testing
• Updated provisions for refrigeration systems including releasable refrigerant charge limits (EDVC framework), machinery rooms, and refrigerant piping/shaft requirements
• New provisions for masonry heaters, including dedicated compliance pathways for listed and site‑built systems
• New provisions for district energy systems, expanding beyond Ambient Temperature Loop (ATL) systems
• New Appendix H providing minimum requirements to address Legionella growth in mechanical systems
• New Appendix K with recommended configurations for maintaining quality of heat transfer fluids in closed‑loop hydronic systems
• New Appendix M providing recommended practice for hydrogen fuel gas piping systems
• New Appendix O addressing minimum mechanical system requirements for tiny houses

The 2027 Uniform Codes will once again be available electronically, meaning that if someone is working from home or in the field and left the code book at the office, it is accessible from a computer or mobile device.

The 2027 UPC and UMC Illustrated Training Manuals (ITM) and Guide to Important Code Changes (GTICC) are also available, offering an additional educational resource designed to support understanding and application of the codes through clear visual interpretation and practical instruction.

The Uniform Codes are developed using IAPMO’s ANSI-accredited consensus development procedures. This process brings together volunteers representing a variety of viewpoints and interests to achieve consensus on plumbing and mechanical practices. The 2027 editions of the UPC and UMC mark the ninth time these codes have been developed in this manner. IAPMO urges its members and other interested parties to get involved in the process to ensure effectiveness in preserving the public’s health, safety, and welfare through fair and balanced development of its codes and standards. Installers, plumbing and mechanical officials, the construction industry, engineers, and manufacturers all benefit from a cooperative effort in developing codes.

Introduced in Los Angeles in 1928 and formally published as the Uniform Plumbing Code in 1945, the UPC is developed to govern the installation and inspection of plumbing systems as a means of promoting the public’s health, safety and welfare. Later published by IAPMO in 1967, the UMC provides the same governance for mechanical (HVAC, combustion, exhaust, refrigeration) systems. Developed and subsequently republished at the conclusion of each three-year code cycle, the UPC and UMC are designed to provide consumers with plumbing, heating, and mechanical systems that meet all applicable standards while, at the same time, allowing latitude for innovation and new technologies.