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The Changing Face of Inspections in Today’s Plumbing Industry

By Bruce Pfeiffer

In the United States, inspections have been an integral part of the construction industry since the inception of national building codes in the early 1900s. The “Hoover Code,” published in 1928 by the United States Department of Commerce, was the first national plumbing code. Article 14, Section 137 of that document stated:

“All piping, traps, and fixtures of a plumbing system shall be inspected by the proper administrative authority to insure compliance with all the requirements of this code and the installation and construction of the system in accordance with the approved plans and the permit.”

In that same year, a group of Los Angeles plumbing inspectors formed an association – the Los Angeles City Plumbing Inspectors Association (LACPIA), whose main purpose was to develop a code which would provide uniform guidelines for plumbing systems in the City of Los Angeles. A few years after its inception, the LACPIA disbanded and formed a new association, the Pacific Coast Plumbing Inspectors Association (PCPIA). The Members of the PCPIA consisted of inspectors and engineers from California and 10 other western states. They were responsible for the development and maintenance of the Standard Plumbing Code. In 1945, the PCPIA transformed into the Western Plumbing Officials Association (WPOA), whose members authored and published the first Uniform Plumbing Code® (UPC) in 1946. Much as it is today, the main objective of the 1946 UPC was to provide minimum requirements and standards for the protection of public health, safety, and welfare. Similar to the Hoover Code, the UPC addressed specific requirements for plumbing inspectors and their assistants, including the qualifications needed to become an inspector and the duties to be performed by inspectors. In 1958, the section of the UPC addressing inspector qualifications was removed from the code, reverting those responsibilities to local jurisdictions.

In 1966, the WPOA became the International Association of Plumbing and Mechanical Officials (IAPMO). The fledgling Association was entrusted by its membership to update and maintain the Uniform Plumbing Code. Over the ensuing 74 years, the UPC has evolved from a booklet that could easily fit into one’s back pocket to a document that covers everything from the installation requirements for potable water distribution systems to the intricacies of medical gas and vacuum systems. Today’s UPC is a complex document that includes not only plumbing installation guidelines, but a vast array of referenced standards by which all products associated with plumbing systems are manufactured and tested.

Although the UPC no longer addresses inspector qualifications, jurisdictions using the code saw the need to employ competent inspectors to oversee the installation of plumbing systems in their cities. Inspectors were expected to be “experts” in their respective trades. They needed to have extensive knowledge of approved materials, installation practices, and product standards. Interpretation of code language was among one of their most essential duties. Most inspectors served apprenticeships in their particular trade and were licensed as journeymen or masters in that trade. They were proficient in plan review, many becoming Certified Plans Examiners. Some advanced their education to include degrees in engineering or other building related fields. They were also expected to be certified in specialty fields such as medical gas and vacuum systems. Sadly, the days of the trade specific inspector are quietly going the way of the dinosaur. Due to budgetary constraints and the desire to reduce personnel in inspection departments, cities throughout the country have opted to employ multi-trade inspectors. These new age inspectors are no longer proficient in the trade or trades they are inspecting and may have never worked in those trades. This trend of employment by jurisdictions makes training and advanced education for today’s inspectors even more imperative.

IAPMO is dedicated to providing their membership with training and education opportunities. This commitment to education is evident by the numerous seminars provided by the association to its members throughout the year and at its Annual Business and Education Conference. Each year, the Uniform Plumbing Code and Uniform Mechanical Code Workshop Committees provide attendees with a three-hour workshop that covers the latest installation requirements found in their respective codes. The illustrations used in the workshop, many embedded with code violations, provide participants with an opportunity to test their code knowledge while brainstorming with fellow inspectors and industry partners. Recently, the IAPMO Training & Education department began using these illustrations as a teaching tool outside of the conference setting to aid in the instruction and development of new inspectors.

The figure below is an example of what you may see at a UPC Workshop. Take a few minutes to review the drawing and determine if it is compliant under the specifications found in the 2018 UPC or if there are violations in the drawing. As the Authority Having Jurisdiction, you have the power to render interpretation of the code as long as that interpretation complies with the intent and purpose of the code.


2018 UPC, Section 908.2.3 – Trap arm lengths for fixtures shall not exceed the limits found in Table 1002.2. Pipe section “A”, the 1-1/2” trap arm for the bathtub may not be longer than 42”.

2018 UPC, Section 210.0 (Horizontal Pipe) – The wye branch for pipe sections “A”, “B” & “C” is rolled at a 45° angle from the horizontal main line, which makes the connection to pipe section “B” vertical. This is not allowed on a horizontal wet vent system.

2018 UPC, Section 908.2.2 – The “red” portion of the diagram, including pipe section “B,” would be considered the horizontal wet vent for the installation. With 3 dfus, it is required to be a minimum of 2”. The dry vent is required to be sized per Table 702.1 and Table 703.2. Serving 5 dfus* the dry vent would also be required to be 1-1/ 2”.

*NOTE: Pipe sections “B” and “C” are the wet vent for the shower and bathtub, which equals 4 dfus.

2018 UPC, 908.2.1 – By inference, fixtures that are part of a horizontal wet vent system must remain horizontal. The water closet connection at pipe section “F” is clearly on the vertical stack. The water closet could not be part of the horizontal wet vent system, but would be required to be separately vented as required in applicable sections of Chapter 9.

Bruce Pfeiffer has been in the plumbing trade since 1975. After serving an apprenticeship, he worked as a journeyman plumber before passing his State of Kansas Master Plumbers examination. In 1989, he took a position with the City of Topeka as a plumbing inspector, becoming senior plumbing inspector in 1997. He retired from the City of Topeka after 28 years of service. Pfeiffer is a proud member of UA Plumbers and Pipefitters Local 441. He is currently a retired member of the Union but continues to provide CEU classes for the local’s journeymen and master plumbers. Pfeiffer has served on numerous IAPMO committees including the UPC Interpretations Committee, UPC Workshop Committee, and UPC/UMC Publications Committee. He served as the chairman for the UPC Workshop Committee for many years and is currently serving on the Standards Research Committee and Products Certification Committees and as chairman of the UPC Answers & Analysis. In 2005, Pfeiffer was elected to the IAPMO Board of Directors, serving for 14 years on the Board, including two years as President of the Association in 2014 – 2016.

Article courtesy of Working Pressure magazine

Last modified: June 29, 2020