Construction
Plumber Job Description
Plumbers install, maintain, and repair water supply, drainage, and gas systems in residential, commercial, and industrial buildings. They work from blueprints and plumbing codes to rough in and finish plumbing systems, set fixtures and equipment, troubleshoot leaks and failures, and ensure compliance with local plumbing codes and health regulations.
Last updated
Role at a glance
- Typical education
- Apprenticeship (3-5 years) or trade school program
- Typical experience
- 3-5 years for journeyman competency
- Key certifications
- Journeyman Plumber license, Master Plumber license, ASSE 6010/6020 Medical Gas Installer
- Top employer types
- Residential service companies, commercial construction firms, healthcare facilities, plumbing contractors
- Growth outlook
- Strong demand driven by workforce shortages and retirements outpacing new entrants
- AI impact (through 2030)
- Largely unaffected; while AI-driven tools like thermal imaging and drain cameras augment diagnostics, the physical nature of installation and repair remains resistant to automation.
Duties and responsibilities
- Install water supply piping — copper, CPVC, PEX, and galvanized — for domestic hot and cold water distribution systems
- Install sanitary drain, waste, and vent (DWV) piping using cast iron, ABS, and PVC pipe in new construction
- Set plumbing fixtures — toilets, sinks, showers, bathtubs, water heaters — and connect to supply and drain systems
- Run gas piping for natural gas and propane appliances including furnaces, water heaters, ranges, and dryers
- Rough in plumbing work during the framing phase: install drain stubs, vent penetrations, and supply rough-in blocking
- Test plumbing systems using air or water pressure tests to verify watertight connections before walls are closed in
- Diagnose and repair leaks, drain clogs, water heater failures, and other plumbing system problems in service calls
- Coordinate with other trades on pipe routing, sleeve locations, and ceiling space requirements to avoid conflicts
- Apply for and manage plumbing permits, schedule inspections, and complete work to pass inspector approval
- Interpret local plumbing codes (IPC, UPC, or local amendments) to ensure installations meet regulatory requirements
Overview
Plumbers install and maintain the water and gas systems that make buildings habitable. Without functioning supply, drainage, and gas systems, a building can't be occupied — and when those systems fail, they create damage, health risks, and urgent calls that need to be answered at any hour.
New construction plumbing follows the building's construction sequence. During framing, the plumber does rough work: laying out drain stacks and horizontal runs through the floor structure, cutting holes in framing for pipe penetrations, installing blocking for wall-hung fixtures, and running supply branch lines through walls and floors. Everything has to be sleeved properly where it passes through concrete or fire-rated assemblies, all drain lines have to have the correct slope, and vent connections have to meet code requirements to prevent sewer gas from entering the building. The rough inspection happens before drywall goes on, and the plumber has to pass that inspection before work can continue.
After drywall is finished and tile work is complete, finish plumbing proceeds: setting toilets on new flanges, connecting sink drains and supply stops, installing shower valves and trim kits, setting water heaters, and connecting dishwashers and other appliances. The final inspection confirms that everything is connected, functional, and code-compliant.
Service work requires different skills. When a homeowner calls because water is seeping through the ceiling, the service plumber has to find the source — which might be in a wall, above a ceiling, or at a distant location from where the water is appearing. Drain cameras, pressure gauges, and thermal imaging help, but the diagnosis often requires plumbing intuition built over years of seeing similar problems. The service plumber who solves the problem correctly on the first visit, leaves the work clean, and communicates clearly with the customer is the one who gets called back.
Gas piping carries responsibility beyond other plumbing work. A gas leak can have catastrophic consequences. Plumbers who install gas systems test every joint to the required pressure, leak-check with a gas detector or soapy water, and understand the combustion requirements and venting configurations for the appliances they connect. The margin for error is zero.
Qualifications
Training pathways:
- UA (United Association) plumber apprenticeship: 5 years combining on-site hours with classroom instruction in pipefitting, blueprint reading, plumbing codes, and safety
- Non-union employer apprenticeship: 3–5 years to journeyman competency
- Trade school programs in plumbing technology (1–2 years for foundational knowledge)
- State apprenticeship program registration (required in many states to work toward licensed status)
Licensing:
- Apprentice Plumber registration (most states)
- Journeyman Plumber license — exam-based, requires documented apprenticeship hours; specific requirements by state
- Master Plumber license — additional experience plus exam; required to pull permits in most jurisdictions
- Medical Gas Installer certification (ASSE 6010, 6020) for healthcare facility plumbing work
Technical knowledge:
- Pipe materials: copper (soldered and press-fit), CPVC, PEX, PEX-A/PEX-B/PEX-C systems; cast iron, ABS, PVC DWV
- Code compliance: IPC, UPC, local amendments; trap arm length, vent size, slope requirements
- Gas piping: CSST, black iron, sizing tables for gas appliances
- Water heater systems: tank water heaters, tankless (on-demand), heat pump water heaters
- Backflow prevention: reduced pressure zone (RPZ) assemblies, double-check valves, testcocks
- Medical gas: NFPA 99 medical gas system design and installation for healthcare
Tools:
- Pipe cutters (copper, cast iron), press-fit tools, soldering equipment
- Drain cleaning: hand snake, drum machine, hydro-jetter
- Pipe camera and locator equipment
- Pressure gauge for testing
- PEX expansion or crimping tools by system type
Career outlook
Plumbing is among the most recession-resistant skilled trades. Every occupied building needs functioning plumbing, and the failure modes that bring emergency service calls don't pause during economic downturns. New construction work is cyclical, but service and renovation work provides a base of demand that persists through slower construction periods.
The workforce shortage in plumbing is well-documented. The UA and plumbing licensing boards consistently report that the number of licensed journeyman and master plumbers is declining relative to demand. Retirements are outpacing new entrants at the journeyman and master level, and the licensing pipeline — 5 years to journeyman, additional years to master — means supply gaps are slow to fill.
Residential new construction plumbing demand has recovered from the 2023–2024 interest rate-driven slowdown in most markets, and multifamily construction has been strong throughout that period. Commercial and industrial construction remains active. Healthcare construction — with its specialized plumbing requirements for medical gas, infection control, and equipment connections — is a durable market with premium compensation for qualified plumbers.
Water-efficient fixtures and systems, driven by code requirements and owner interest in reducing water and energy costs, have created a body of product knowledge that plumbers are expected to have: low-flow fixtures, recirculating hot water systems, greywater reuse, tankless water heaters, and heat pump water heaters. Plumbers who stay current on these technologies are valuable to clients who want efficient systems.
Career advancement from journeyman runs to master plumber, which opens the path to pulling permits independently and operating a plumbing business. Many plumbers start small plumbing businesses after earning master status — the capital requirement is modest (tools, truck, license bond and insurance), and a service book of repeat clients provides sustainable revenue. Others move into plumbing estimating, project management, or inspection and code enforcement roles.
Sample cover letter
Dear Hiring Manager,
I'm applying for the Journeyman Plumber position at [Company]. I completed my five-year UA apprenticeship with Plumbers Local [Number] and have held a journeyman license in [State] for three years, working primarily on commercial new construction — multifamily residential and office tenant improvements.
My new construction experience spans full project cycles: rough-in during framing, coordination with the GC and other trades on sleeve and penetration locations, rough inspection, and finish plumbing after drywall. I'm proficient with copper, PEX, cast iron, and ABS/PVC DWV and have worked with both soldered and press-fit copper on commercial projects.
The most complex rough-in work I've done was on a 92-unit apartment building where we ran all domestic water supply in PEX-A manifold systems from central manifold locations on each floor. The coordination with the framing contractor to get blocking installed correctly and protect our PEX lines during subsequent trades was something we worked through carefully, and we had no punctures or damage on the final water pressure test.
I hold my medical gas ASSE 6010 certification — I completed the training program two years ago and have installed medical gas rough-in in two dental office tenant improvements since then.
I'm looking for a company with more commercial and healthcare plumbing work. [Company]'s project mix in that sector is exactly the direction I want to develop in. I'd welcome the opportunity to discuss the position.
[Your Name]
Frequently asked questions
- What does a Plumber do?
- Plumbers install, maintain, and repair water supply, drainage, and gas systems in residential, commercial, and industrial buildings. They work from blueprints and plumbing codes to rough in and finish plumbing systems, set fixtures and equipment, troubleshoot leaks and failures, and ensure compliance with local plumbing codes and health regulations.
- What are the main duties of a Plumber?
- Core duties include: install water supply piping — copper, CPVC, PEX, and galvanized — for domestic hot and cold water distribution systems; install sanitary drain, waste, and vent (DWV) piping using cast iron, ABS, and PVC pipe in new construction; and set plumbing fixtures — toilets, sinks, showers, bathtubs, water heaters — and connect to supply and drain systems.
- What licenses do Plumbers need?
- Plumbing licenses are issued by state or local authorities and come in tiers. An Apprentice Plumber works under supervision. A Journeyman Plumber has passed a licensing exam demonstrating knowledge of the trade and applicable codes and can perform work independently but typically not pull permits. A Master Plumber has additional experience, has passed a more comprehensive exam, and can apply for permits and run a plumbing business. Requirements vary substantially by jurisdiction — some states have statewide licensing, others regulate at the county or city level.
- What is the difference between rough plumbing and finish plumbing?
- Rough plumbing happens before walls are closed in — it involves running supply pipes, drain pipes, and vent pipes through the framing of the building. The work needs to pass rough inspection before drywall can proceed. Finish plumbing happens after drywall and tile work is complete — installing fixtures, connecting supply stops to fixtures, setting water heaters, and completing visible connections. Both phases are required on every plumbing job.
- What is a plumber's most important tool for diagnosing problems?
- Experience and systematic thinking are the most valuable diagnostic tools — understanding how plumbing systems work and what symptoms point to which problems. The physical tools that help diagnosis include drain cameras (for viewing blockages and pipe damage), pressure gauges (for leak testing), thermal cameras (for finding hidden water leaks in walls), and multimeters for electric water heater diagnostics. A plumber who can accurately diagnose the problem on the first visit saves significant time and earns client trust.
- What is the difference between a plumber and a pipefitter?
- Plumbers install domestic systems in buildings: water supply, drainage, and gas for occupant use, regulated by the International Plumbing Code or Uniform Plumbing Code. Pipefitters install industrial and commercial process piping — steam, chilled water, process chemicals, compressed air — that serves equipment rather than occupants, regulated by ASME codes. The trades use many similar skills but different materials, code frameworks, and project types.
- Is plumbing affected by smart home technology?
- Smart water shutoff valves, leak detection sensors, and connected water heaters are increasingly common in new construction and renovation. Plumbers install these systems alongside traditional plumbing work, and some systems require basic programming or app configuration that plumbers need to know. Water usage monitoring and remote shutoff capability are valuable features for homeowners and commercial property managers, and plumbers who understand these systems are more useful to clients who want them.
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