My vision is to advance the plumbing and mechanical industry through expert code knowledge, practical innovation and collaborative leadership. I create free tools and educational resources for industry professionals, advocate for thoughtful public policy and promote safer, more efficient and sustainable building systems. By connecting contractors, inspectors, engineers, manufacturers and policymakers, I work to turn complex challenges into practical solutions that strengthen our workforce, protect public health and move the industry forward.

A man with a bald head, glasses, and a beard, wearing a suit and tie, smiling against a yellow background.

John A. Mullen is a fourth-generation plumber, nationally recognized plumbing and mechanical subject matter expert, and construction industry leader with nearly two decades of experience. As Director of Technical Services and Research for IAPMO, he provides technical guidance on the Uniform Plumbing Code (UPC) and Uniform Mechanical Code (UMC), supports engineering and code-development initiatives, and helps advance emerging technologies from innovative concepts to practical industry applications.

John is also the founder and CEO of Throw a Wrench in Your Plans Media, where he creates free tools, technical resources and digital content for contractors, inspectors, engineers and the next generation of skilled tradespeople. His work explores building codes, artificial intelligence, emerging technology, workforce development and the future of the plumbing and mechanical trades.

A published author, technical columnist, speaker and policy advocate, John contributes to professional committees, standards-development initiatives and industry organizations across the country. He is passionate about protecting public health, strengthening the skilled trades and developing smarter, more resilient and sustainable building systems—including hydronic, geothermal and heat-recovery technologies that use water to move, store and recover energy.

John’s mission is simple: bring new energy, practical innovation and a tradesperson’s perspective to the future of the built environment. 🚀

Throw a Wrench in Your Plans An Atlas to the Industry
Built by a fourth-generation plumber

Ask a Plumber: Should I Worry?

Pick the problem and get a practical gut check before a small leak becomes a full-blown Saturday project with four trips to the supply house.

Need a real set of eyes on it?

This tool helps homeowners stop guessing. It is not a substitute for a licensed professional, especially when water, sewage, gas, electricity, or pressure are involved.

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Disclaimer: This widget provides general homeowner education only. Plumbing systems vary by home, local code, product listing, installation, water pressure, age, and maintenance history. When in doubt, shut off the affected fixture or main water supply if safe to do so and call a licensed plumber.