When Cities Were Killing Their Own People
Picture this: it's 1849. You live in New York, Boston, or Cincinnati. The city is growing fast -- too fast. Water comes from a shallow well dug close to a leaking cesspool. Sewage runs down the middle of the street. Nobody thinks twice about it.
Then cholera hits.
Three waves of cholera struck the United States in the 1800s -- in 1832, 1849, and 1866. Outbreaks in North America in the 1870s killed some 50,000 Americans as cholera spread from New Orleans up the Mississippi River and its tributaries. None of the cities had adequate sanitation systems, and cholera spread through the water supply and direct contact.
The problem was not a mystery, at least in hindsight. Sewage was deposited by individual households into streams or cesspools that were allowed to overflow, and water sources and sewage disposal were positioned for convenience, not safety -- often so close together that the odor and taste of drinking water was a problem.
Cities were not just failing their residents. They were actively poisoning them.
The Crisis That Built a Trade
The epidemics did not just kill people. They forced cities to act. After the outbreaks of 1849 and 1866, Boston began overhauling its sewerage system. By 1875, the city had launched a study on pollution and water contamination, which prompted a newly designed sanitation system completed and functional by 1884.
Other cities followed. Chicago had a particularly grim situation. Chicago relied on Lake Michigan for its water supply, but the city's sewage system drained directly into the lake via the Chicago River. The typhoid mortality rate reached 33.7 per 100,000 per year, and the city suffered repeated outbreaks of cholera and typhoid in the late 19th century. In 1900, the Chicago Sanitary and Ship Canal was completed, reversing the flow of the Chicago River so that sewage would no longer empty into Lake Michigan.
These were not small projects. They required armies of skilled workers who could plan, lay pipe, and connect systems at a scale nobody had attempted before. The demand for plumbers who could install sanitary systems -- not just fix a leaking joint, but design and build entire networks under a city -- created the trade as we know it today.
As Lewis Thomas summed it up: "Much of the credit should go to the plumbers and engineers of the western world. The contamination of drinking water by human feces was at one time the greatest cause of human disease and death for us, but when the plumbers and sanitary engineers had done their work in the construction of our cities, these diseases began to vanish."
That quote is not a footnote. It is the whole story.
Codes, Licenses, and the Fight to Professionalize
Early plumbing was a free-for-all. Anyone could call themselves a plumber and charge for work that could quietly kill a family within months. The chaos was not just a public health problem -- it was an economic and political one.
By the 1850s, major cities such as New York had introduced significant plumbing requirements, including licensing and plan submission, all regulated by health code provisions. But the rules were fragmented and inconsistent. What passed inspection in one city was illegal in the next.
The pressure to standardize finally reached Washington. In 1906, a group of sanitary professionals gathered in Washington D.C. under the direction of Henry B. Davis and formed the American Society of Sanitary Engineering (ASSE). Davis envisioned a group that could exchange ideas and try to standardize the different plumbing and sanitary codes throughout the country.
Even so, the patchwork persisted. As Secretary Hoover stated in 1924: "Actual practice has been governed by opinions and guesswork, often involving needless costly precautions which many families could ill afford. The lack of generally recognized principles is responsible to a certain extent for the contradictory plumbing regulations in different localities."
His response was direct. Hoover started the Materials and Structures Division of the National Bureau of Standards and appointed Dr. Roy Hunter to the plumbing division. Hunter conducted a series of research studies on how to best handle various aspects of plumbing, forming the basis of modern plumbing codes. Once the codes were created, new housing was built with complete plumbing facilities -- hot and cold piped water, a bathtub or shower, and a flush toilet.
This professionalization mattered for workers too, not just consumers. Licensed tradespeople could command better wages, build legitimate businesses, and hold employers and developers accountable when they cut corners. A code is not just bureaucracy. It is the floor below which no one is allowed to put people's lives at risk.
From Wooden Logs to PEX: The Materials Revolution
Here is something most people do not know: the first water mains in North American cities were literally trees.
U.S. cities began using hollowed logs for water distribution in the late 1700s through the 1800s. In the early 1800s, firefighters realized they could bore into the logs to access water, helping them fight fires more effectively. That boring point became the origin of the term "fire hydrant."
Wooden water mains remained the material of choice for water distribution until the early 1900s, when plumbing piping took a huge leap in durability and flow characteristics with the advent of sand-cast, cast iron water main.
Cast iron was a major upgrade -- stronger, longer lasting, and far more sanitary. But it was heavy, brittle, and required specialized skills to cut and join. Plumbers who had worked with wood and lead now had to learn an entirely different material. That pattern of forced retraining would repeat itself throughout the century.
The earliest indoor systems used cast iron, steel, galvanized steel, lead or brass -- but an inexpensive, easy-to-produce, longer-lasting pipe material, thin-wall copper tubing, created a revolution that helped modernize the nation. Introduced around 1927, copper tubing eventually grew to account for about 90% of indoor water piping. To date, more than 5.7 million miles of copper tubing have been installed in homes and commercial buildings in this country.
Copper required new skills again -- soldering, sweating joints, working with soft and hard material in tight spaces. Then came plastics.
Cross-linked polyethylene, or PEX, has become increasingly popular as a pipe material in residential plumbing. Introduced in Europe during the 1970s but only gaining popularity in North America by the late 1980s and early 1990s, PEX offers several advantages. It is flexible, which allows it to be installed with fewer joints, reducing potential leak points. It is also resistant to both corrosion and scale buildup, which can affect flow rates over time with other materials like copper or iron.
Each material shift was not just a product swap. It meant new tools, new training, new inspection requirements, and new failure modes to understand. The plumbers who stayed ahead were the ones who treated every change as a skill upgrade, not a threat.
What This Means for You Right Now
That same pattern is happening today. The materials are not changing this time -- the systems around them are.
Technological features now demanded by the market include touchless faucets, voice activation, water-saving devices, and push-fit connections. Personal electronics -- such as shower valves that automatically set temperatures and individualized spray modes -- are complementing plumbing products. Integrated systems can now alert homeowners of adverse conditions such as constantly running water or breaks and leaks in pipes.
AI-assisted leak detection, smart water monitoring, and building automation systems are not coming. They are here. The plumbers who understand how to commission these systems, read the data they generate, and troubleshoot a sensor-based alert alongside a mechanical failure -- those are the plumbers who will own the premium tier of this market.
Here is what to do:
- Get comfortable with smart water technology. Learn one platform well -- Moen Flo, Phyn, or similar.
- Study the code cycles. The International Plumbing Code and Uniform Plumbing Code both update every three years. Staying current is a competitive edge.
- If you run your own shop, look at AI-assisted estimating and scheduling tools. Your competitors are not using them yet. That is an opportunity.
- If you are new to the trade, do not just learn how to sweat copper. Learn how the whole system works, from source to drain. That systems thinking is what separates a good plumber from an indispensable one.
The plumbers who built the sewer systems of Chicago, laid copper through millions of post-war homes, and retrained for every material shift in between were not just keeping the water running. They were keeping people alive.
That work continues. The tools are different. The stakes are the same.