“Plumber” covers a dozen very different jobs. The guy snaking a drain at 2 a.m. and the hand welding process pipe in a refinery both hold plumbing tickets, but their days, pay, and skills barely overlap. Here’s the map of plumbing work — inside and outside, residential to industrial — so you can see where you’d fit.
The biggest split is what kind of building you work in. Residential is houses and small multifamily. Commercial is offices, schools, hospitals, and restaurants — bigger systems, more code, more coordination. Industrial is plants and refineries, where the work is process piping and often blends into pipefitting. Complexity and pay generally climb as you move up that ladder.
The other big fork is service versus new construction. Service and repair means existing buildings — troubleshooting, callbacks, customer-facing work, and being on call; residential service in particular has strong money, especially if you go out on your own. New construction means rough-in and then trim on new builds — production work with crews, less diagnosing, more installing. They suit different personalities.
“Inside” plumbers run the building’s water, waste, and vent within the structure. “Outside” or site work is the underground and yard piping — water and sewer mains, storm lines, and the laterals that tie a building to the street — done in the trench alongside the excavation crews. Municipal and utility water/sewer is its own outside world, closer to underground construction than to service plumbing.
Drain cleaning, jetting, camera inspection and locating, and trenchless repair (pipe bursting and CIPP lining) are a high-demand niche. It’s dirty, well-paid service work, and plenty of plumbers build a standalone business around it.
This is where plumbing bleeds into pipefitting and steamfitting — process piping, boilers and steam, fuel gas, and medical gas. It’s top-dollar plant, refinery, and turnaround work, and it’s where the highest technical pay in the pipe trades lives.
Certifications open doors and raise pay: medical gas installer, backflow prevention tester, water treatment, hydronics and radiant heat, gas fitting, and fire sprinkler (often its own trade). Stacking a specialty onto a journeyman ticket is one of the fastest ways to move your rate.
Industrial and certified specialties (medical gas, steam, process) and self-employed residential service tend to top the pay scale; new construction is steadier but often lower per hour. Choose by how you like to work: troubleshooting and customers (service), production with a crew (new construction), or heavy and technical (industrial).
Compare lifetime earnings, debt, and net worth — the trade vs a four-year degree.
Run the Wealth Calculator → How to become a plumber →