BLS tracks "Plumbers, Pipefitters, and Steamfitters" as a single occupational code (47-2152) — which is administratively convenient and genuinely obscures that these are three related but distinct jobs, with real pay differences between them.
Plumber
The work: water supply, drain-waste-vent systems, fixtures — the systems inside homes and commercial buildings that carry potable water in and waste out. Residential and light commercial service and installation.
The setting: houses, apartments, small commercial buildings — the widest variety of daily work and the most direct customer contact of the three.
Pipefitter
The work: piping systems that carry process fluids, gases, and chemicals in commercial and industrial settings — HVAC piping, process piping in manufacturing, refrigeration systems. Distinct from plumbing in that the piping often isn't carrying potable water or sewage at all.
The setting: commercial buildings, manufacturing plants, refineries, and power plants — typically larger-scale, more industrial environments than general plumbing.
Steamfitter
The work: a pipefitting specialty focused specifically on high-pressure steam systems — power generation, heating plants, and industrial process steam. The highest-pressure, highest-stakes end of this occupational family.
The setting: power plants, large industrial facilities, institutional heating plants (hospitals, universities running steam-based systems).
Why the Pay Differs
| Plumber | Pipefitter | Steamfitter | |
|---|---|---|---|
| Typical setting | Residential/light commercial | Commercial/industrial | Industrial/power generation |
| Pressure/stakes | Standard water pressure | Variable, often higher | High-pressure steam |
| General pay pattern | Trade baseline | Above baseline | Often highest of the three |
The pattern holds across the industry: industrial and high-pressure work generally out-pays general residential plumbing, for the same reasons industrial electrical out-pays residential electrical (the parallel case in electrical) — higher stakes, more specialized training, fewer qualified workers, and often unionized industrial settings with negotiated scale plus benefits.
"Plumber" on a paycheck stub can mean three genuinely different careers depending on what's actually running through the pipe — potable water, process fluid, or high-pressure steam. The distinction is worth knowing before you specialize.
How the License Connects Them
In most states, the same journeyman plumbing license provides the legal foundation for all three — the specialization comes from training, employer, and often additional certification (particularly for steamfitting, which frequently layers in welding credentials) rather than a completely separate licensing track. That means a plumber can realistically move toward pipefitting or steamfitting work later in a career without starting over, given the right training and employer.
Which Path to Choose
If direct customer contact, daily variety, and residential/light-commercial work appeal — general plumbing. If higher pay and industrial/commercial settings appeal, and the tradeoff of more standardized, larger-scale work is acceptable — pipefitting. If the highest pressure, highest stakes, and often the highest pay in this family sound right — steamfitting, typically reached through UA training and often paired with welding certification (specializations guide).