Why is the left faucet handle always for hot water? (Part 1)

You don’t truly know what you’ve have until it’s gone. The sink in my apartment’s bathroom was installed incorrectly and the right faucet handle controls hot water, while the left one controls cold water. It’s a disorienting experience to say the least.

So often I bury the lede and go on tangents, inflating the scale of the problem, but we have a lot of ground to cover this time, so let’s cut to the chase: why is the right faucet handle always for cold water?

The answer to our question is quite simple: a Mental Floss article by Amanda Green claims that the Uniform Plumbing Code (UPC) published by the International Association of Plumbing and Mechanical Officials (IAPMO) requires it. If what Amanda Green claims is true, how does this 442-page document compete with the Constitution, full of the wisdoms of our Founding Fathers, or the Bible, the word of God Himself, to have this much power of over lives? As our mission to expose uncomfortable truths and hold power to account, impartially and unflinchingly, we will seek dismantle the Uniform Plumbing Code by uncovering its dark origins and revealing the true intentions of its authors.

Where two separate handles control the hot and cold water, the left-handed control of the faucet where facing the fixture fitting outlet shall control the hot water.

Separate Controls for Hot and Cold Water, U.P.C. § 417.5 (2018)

Has any other sentence this much power over our lives? How have these 27 words come to control every facet and faucet of our existence.

The first iteration of the now all-powerful Uniform Plumbing Code was written by a group of plumbing inspectors in 1926 Los Angeles, borne out of their appreciation for uniformity and codification. The code was adopted by the city in the following years and then by the Western Plumbing Officials Association in 1945. Its adoption spread across multiple jurisdictions in the United States for the next several decades. The 2003 Uniform Plumbing Code was developed by the IAPMO in conjunction with the American National Standards Institute (ANSI) and is considered, by the IAPMO at least, to be a significant milestone in the long and storied history of plumbing codes in the United States. All of this is according to a poorly sourced Wikipedia article.

Publishing the 2003 Uniform Plumbing Code, is a significant milestone because it is the first time in the history of the United States, a plumbing code was developed through a true consensus process.

U.P.C. Foreword (2018)

That sentence has existed in every edition of the Uniform Plumbing Code, which is published every three years, since 2003. The IAPMO seems to be especially proud of their 2003 magnum opus; could it be because that’s when this rule that has come to pervade our everyday lives was first codified? Looking at that seminal piece of work, we find that it, too, contains provisions for how to separate the hot and cold water faucet handles, but it is not the first occurrence of the rule. To find that we will have to become plumbing code archeologists.

Where two separate handles control the hot and cold water, the left hand control of the faucet when facing the fixture fitting outlet shall provide the means to alter the hot water temperature from the fixture fitting.

Installation of Fixture Fittings, U.P.C. §416.0 (2003)

The IAPMO, ashamed of their past, has attempted to cover their tracks and removed editions older than 2012 from their website. With the backing of the investigative powerhouse that is Quoc Thoughts (alongside the UC San Diego Library and the Internet Archive), I been able to access every edition of the Uniform Plumbing Code published since 1988 (and a hard copy of the 1958 edition, which includes some pretty fun advertisements). The first mention of this standard, which I, as its foremost expert, have since dubbed the “lefty hotty righty coldy” rule, appears in the 1997 edition of the Uniform Plumbing Code.

Faucets and diverters shall be installed so that the flow of hot water from the fittings corresponds to the left hand side of the fitting.

Installation of Fixture Fittings, U.P.C. §416.0 (1997)

Since their now-viral 2003 collab with ANSI, it’s clear that the IAPMO considers their Uniform Plumbing Code to be the end-all-be-all of plumbing codes worldwide, but, according to this webpage about State Plumbing Codes Useful For Plumbing License Exams, its adoption is mixed at best. In the United States, only 13 states (Alaska, California, Hawaii, Idaho, Indiana, Iowa, Missouri, Montana, Nevada, New Mexico, Oregon, South Dakota, and Washington) either use the Uniform Plumbing Code or an adaptation of it; the overwhelming majority of the others (30 states) use the International Plumbing Code (IPC) developed by the International Code Council (ICC). It seems as if Amanda Green at Mental Floss has misled us with her claim. Mental Floss? More like Mental Gingivitis, am I right?

There is no question that Amanda Green at Mental Floss is an agent of the ICC, working to hide their true influence over the world of plumbing standards, all the while writing articles like 6 Flight Attendants Gone Wild and 15 More Quirky Menorahs to hide her true intentions. The original premise of my article was a takedown of the IAPMO and its hold over our faucets nationwide and I have spent countless days and nights, poring over dense plumbing codes, reading frankly hilarious meeting minutes, and navigating badly-designed websites in pursuit of the important hard-hitting investigative journalism that was designed to bring about the complete and utter destruction of the IAPMO. However noble my intentions, they were clearly misguided.

This leads us to a logical next question: what does the ICC, the hidden superpower of plumbing standards that they are, have to say about the “lefty hotty righty coldy” rule in their competing International Plumbing Code? Due to my lack of funding (my Venmo is @quoctran98 and my Patreon is online as well), I am not able to purchase the latest 2015 International Plumbing Code. The 2012 edition (it also seems as if the ICC publishes their codes every three years as well), which is the latest easily accessed iteration of the the Code enforces the “lefty hotty righty coldy” rule, with much the same wording as the Uniform Plumbing Code.

Fixture fittings, faucets and diverters shall be installed and adjusted so that the flow of hot water from the fittings corresponds to the left-hand side of the fixture fitting.

Flow of hot water to fixtures, I.P.C. §607.4 (2012)

Even more secretive than the IAPMO, the ICC has no Wikipedia article, so it is quite literally impossible to know how they were formed and how they rose to possess so much power. Obfuscated in such mystery, past editions of the International Plumbing Code can only be found by a talented and courageous internet archeologist. Truly the Indiana Jones of plumbing codes, I have tracked down the year 2000 edition of the International Plumbing Code. According to the introduction of this edition of the Code, it was first published in 1994, but we’ll have to settle third iteration of the International Plumbing Code because there seems to be no hard, soft, or even medium copy of the 1994 or 1997 International Plumbing Code available on any archive or interlibrary loan system.

These two editions of the Code have been erased from the collective human consciousness, much like the plot to James Cameron’s Avatar and whatever happened to Kony in 2012. Unfortunately, the 2000 edition of the International Plumbing Code also includes the “lefty hotty right coldy” rule. It’s clear that this rule must have appeared in the International Plumbing Code for the first time sometime between 1994 and 2000, pretty much the same exact time as this standard became codified in the 1997 edition of the Uniform Plumbing Code.

The hot water supply to any fixture shall be installed on the left side of the fixture.

Hot water supply to fixtures, I.P.C. §607.4 (2000)

The question has been answered: the “lefty hotty righty coldy” rule first became codified in the 1990s, a decade-defining event, comparable to Mariah Carey’s rise to fame, the Y2K scare, and the death of Princess Diana.

But we actually haven’t answered any questions at all. What actually happened in the 1990s that led to the codification of the “lefty hotty righty coldy” rule?

This is only the beginning. I’ve written nearly 1500 words documenting my journey through plumbing codes, but I haven’t even addressed the true question at the heart of this topic. Most of my articles are a waste of time, but this one was especially bad.

Keep an eye out for part two, where I waste even more of your and my time by delving into the time before time itself and taking a look back at 1990s America to uncover the true dark origins of our old friend, the “lefty hotty righty cold” rule.

4 thoughts on “Why is the left faucet handle always for hot water? (Part 1)

    • Mixing faucets were outside the scope of my research, but I do find it interesting how most of these faucets can modulate the ratio of hot to cold water by moving left to increase the amount of hot water and vice versa. Nowhere is this codified, to my knowledge, but it’s a standard that plumbers adhere to when installing these fixtures. I’ll talk more about where this standard comes from in part 2, so keep an eye out for that!


  1. Pingback: Why is the right faucet handle always for cold water? (Part 2) | Quoc Thoughts

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