Plumbers install and repair water, gas, and other piping systems in homes, businesses, and factories — the piping occupants use, plus the fixtures and appliances attached to it.
Steamfitters specialize in systems that move liquids or gases at high pressure: steam, hot water, chilled water, compressed air.
This guide compares the systems each trade works on, how training and union locals differ, where licensing splits, and what the pay data can and cannot tell you.
Plumber vs steamfitter: the short answer
The difference is the pressure and the people the pipe serves.
Plumbers work on the piping a building's occupants use — water, gas, and other piping systems, with the fixtures and appliances attached to them.
Steamfitters work on systems built for liquids or gases at high pressure — steam and hot-water systems among them.
Same craft family, different medium: pick your trade by picking the piping you want to be responsible for.
| Plumber | Steamfitter | |
|---|---|---|
| Systems (BLS scope) | Water, gas, and other piping systems; fixtures such as bathtubs and toilets; appliances such as dishwashers and water heaters | Systems for the flow of liquids or gases at high pressure — steam, hot water, chilled water, and compressed air, per the United Association's description |
| Works | Homes, businesses, and factories | Mostly manufacturing, commercial, and industrial settings |
| Federal data | One combined occupation — 47-2152, Plumbers, Pipefitters, and Steamfitters | |
| Median pay (May 2025) | $63,800 a year for the combined occupation; no separate plumber or steamfitter wage exists | |
That one-occupation point is not a quirk of the table.
O*NET merged the old Plumber code (47-2152.02) and the old Pipe Fitters and Steamfitters code (47-2152.01) into a single occupation, 47-2152.00, and the old codes are "no longer in use."
Federally there is one occupation here, not two.
Each trade's full picture lives in its own guide — our plumber career guide and steamfitter career guide — and the third member of the family, process piping, is covered in plumber vs pipefitter.
The systems each trade works on
Plumbers install and repair water, gas, and other piping systems in homes, businesses, and factories.
The named fixtures are bathtubs and toilets; the named appliances are dishwashers and water heaters.
It is the piping a building's occupants drink from, bathe in, and heat with — and it runs at the modest pressures of a supply and drainage system.
Steamfitters sit on the other side of that pressure line.
BLS describes pipefitters and steamfitters as installing and maintaining pipes that may carry chemicals, acids, and gases, mostly in manufacturing, commercial, and industrial settings — and steamfitters specifically as specializing in systems designed for the flow of liquids or gases at high pressure.
The United Association describes its steamfitters as fabricating, installing, maintaining, and repairing high-pressure systems that move steam, hot water, and other industrial fluids, chilled water and compressed air included, with welding, rigging, and hydrostatic and pneumatic testing in the work.
So the dividing line is pressure and purpose.
Low-pressure supply lines and the fixtures they feed are plumbing scope; pressurized steam and hot-water systems serving a plant or facility are steamfitter scope.
One reality both trades share: BLS says most plumbers, pipefitters, and steamfitters work full time, including nights and weekends, and are often on call to handle emergencies.
Training and union locals
The entry route is the same for both trades.
BLS says most plumbers, pipefitters, and steamfitters learn through a 4- or 5-year apprenticeship with about 2,000 hours of paid on-the-job training each year, plus technical instruction — and that unions, trade associations, and businesses sponsor the programs.
The union side of that sentence is the United Association (UA), whose apprenticeships it describes as registered with the U.S. Department of Labor and typically lasting five years, with tracks that include plumbing, pipefitting, HVACR, welding, sprinkler fitting — and steamfitting as its own track.
Inside the UA, plumbers and steamfitters are listed as separate trades — the union says it represents approximately 409,000 plumbers, pipefitters, sprinkler fitters, HVACR service technicians, welders, and related trades across North America — but local structure varies.
Some cities run a dedicated steamfitters' local: the Enterprise Association of Steamfitters Local 638 is the NYC steamfitters' union, and the UA locals serving DC split as Local 5 for plumbers and Local 602 for steamfitters.
Other locals train both trades under one roof — UA Plumbers & Steamfitters Local 131 in New Hampshire runs a single 5-year apprenticeship covering plumbing, pipefitting, steamfitting, and HVACR.
Which local covers which work, and what membership costs, varies by local, so ask the local hall where you want to work.
For how membership itself works, see our guide to the plumbers and pipefitters union.
And both trades hire from this board: browse open plumber jobs and steamfitter jobs.
Licensing
Plumbing's licence ladder is the familiar one — but it is not national.
As of September 2026, 24 states have a statewide plumber licence running apprentice or trainee, journeyman, then master, and 4 more (Alaska, New Mexico, Oregon, and Washington) license a journeyman level without a state master licence.
Not every state licenses plumbers at the state level at all: Florida, Kansas, Missouri, Nebraska, Nevada, New York, Ohio, and Wyoming verifiably have no general state plumber licence — licensing there is local, runs through an industry board, or covers contractors rather than workers.
Steamfitting rarely carries its own name on a credential.
Where states license high-pressure piping, the licence is usually called mechanical or pipefitter: mechanical licences that include process piping but not plumbing were found in Michigan, Virginia, Oklahoma, and New Mexico, and Minnesota licenses master and journeyworker pipefitters specifically for high-pressure steam and process piping.
Omaha is an example of a jurisdiction that does license steamfitters by name — master and journeyman levels, each by exam — while New York City has no steamfitter licence at all: its skilled-trade list runs to Master Plumber and High Pressure Boiler Operating Engineer, and steamfitting there is associated with union Local 638.
The practical takeaway: plumber and steamfitter are different credentials where both are licensed, and the licence that covers a high-pressure job depends on the state — and often the city or county — you work in.
Licensing is state and local — confirm before you rely on it
Pay: what the data can and cannot show
Start with the honest limit: there is no plumber-only or steamfitter-only federal wage.
Because BLS combines plumbers, pipefitters, steamfitters, and sprinkler fitters in one occupation (47-2152), any BLS plumber-vs-steamfitter pay comparison is impossible from federal data — the combined code's example titles run from Plumber and Master Plumber to Steamfitter and Gas Plumber.
Anyone quoting separate medians for the two trades is not quoting BLS.
What BLS does publish is the combined occupation, measured by the Occupational Employment and Wage Statistics (OEWS) survey for May 2025, released May 15, 2026.
The median wage was $30.67 an hour, or $63,800 a year — half earned more, half less.
The mean was $34.70 an hour, or $72,170 a year.
The spread is wide: workers at the 75th percentile earned $40.92 an hour ($85,110 a year), and workers at the 90th percentile earned $52.13 an hour ($108,420 a year).
The occupation had 465,840 wage-and-salary jobs, and BLS projects 6.8 percent employment growth from 2025 to 2035 — above the 3.5 percent all-occupation average — with about 42,000 openings a year.
One defensible signal points toward the steamfitter side of this page — sort of.
The highest-paying industries in the combined occupation are industrial ones: electric power generation, transmission and distribution ($115,310 median), petroleum and coal products manufacturing ($106,550), and pharmaceutical and medicine manufacturing ($105,800) — small niches, not typical jobs.
BLS does not say which trade those workers belong to, so read that as a setting effect, not a steamfitter premium.
The survey also excludes overtime pay, shift differentials, and nonproduction bonuses, so workers who log overtime can out-earn the published figures.
For the state-by-state numbers, see the plumber salary page and the steamfitter salary page — both report the combined-occupation data behind the role you search.
This page is career information, not legal or licensing advice. Licensing requirements are set by state boards and local jurisdictions and change — confirm anything you rely on with your state licensing board or local building department.