What Is a Plumbing Qualifying Agent?

What does a plumbing contractor license cover?

It covers installing, repairing, altering and maintaining the systems that bring safe water into a building and carry waste out of it: water supply piping, drain, waste and vent piping, fixtures, water heaters, backflow preventers and storm drainage. In many states it also covers fuel gas piping to appliances and specialty piping such as compressed air and medical gas. Where the license stops varies more in plumbing than in most trades. The heating and cooling equipment belongs to the HVAC contractor, though in many states the plumber may still run the gas line to it, and some states split gas piping into a separate gas fitter license. The power wiring to a water heater or pump belongs to an electrician. Fire sprinklers are usually their own fire protection license. Pool and spa piping is handled by pool contractors in some states and plumbers in others. Plumbers typically handle a building's own water and sewer service lines, while the mains in the street and larger site utilities often belong to underground utility or pipeline contractors (learn more about your state here).

What does a qualifying agent do in plumbing?

The qualifier is the licensed person responsible for all the plumbing work the business contracts for. In many states the qualifier must hold the top individual credential, usually master plumber, and register as the license holder responsible for the company. In other states the plumbing contractor license is itself the qualifying credential. Permits are pulled under the qualifier's license, and inspectors check the piping at stages such as underground, rough-in and final, so the qualifier is accountable when work fails. That covers the jobs themselves, from service calls, drain cleaning, water heater replacements and repipes to new-construction rough-in and commercial systems, and the crews doing them. Journeyman plumbers and apprentices do most of the hands-on work. Apprentices work under the supervision of licensed plumbers, and in some states each plumber on the crew needs their own state credential.

A master who only lends a name to a permit isn't supervising, and that's a license rental. See our guides on how the qualifying agent relationship actually works and renting or leasing a contracting license.

Does plumbing need its own license, or can another license cover it?

Plumbing needs its own license. A general contractor license doesn't let a GC do plumbing work itself. The GC can include plumbing in its contract but subcontracts it to a licensed plumbing contractor, unless the GC also holds the plumbing license. Other trade licenses don't cover plumbing either, apart from narrow overlaps such as an HVAC contractor disconnecting and reconnecting lines during an equipment changeout, where a state allows it. What varies by state is who issues the license, how the trade is split (some states give gas piping, fire sprinklers, pool piping, drain cleaning or site utilities their own licenses or registrations), and whether individual plumbers must work for a licensed plumbing company (learn more about your state here).

What does it take to get licensed in plumbing?

Plumbing is licensed in two layers. The individual credentials are apprentice, journeyman plumber and master plumber, and some states add limited or restricted tiers. The contractor license is separate and authorizes the business to contract. In many states the contractor license requires a master plumber as the qualifier. Specialty work often needs its own certification on top of the plumbing license. Medical gas piping in health care facilities usually needs an installer certification, testing backflow prevention assemblies commonly needs a tester certification (often set by the water utility or health department and not the plumbing board), and some states issue their own endorsements for medical gas, water supply protection or residential fire sprinklers. The work is governed by one of two national model plumbing codes: the International Plumbing Code (IPC) or the Uniform Plumbing Code (UPC), which is used mainly in western states. Both are updated every three years and only become law when a state or city adopts them, usually with amendments. See our guides on what experience is required, how to gain experience, and what education is required.

What else should you know?

Most of what applies to any trade is covered in our guides. See starting a contracting business without a license and how long you have to replace a qualifying agent for when a business needs a qualifier, renting or leasing a contracting license for why renting isn't an option, and the state-by-state directory for how requirements differ. See all ten trades on our trades page, and the full list of guides on our guides page.

How do you find a plumbing qualifier or a business hiring one?

findQualifier.com is a public, searchable board of licensed professionals advertising their availability to work as a qualifier, by state and trade. Browse available qualifiers, browse businesses looking to hire, or post a listing.