Plumbing contractor license requirements by state: what the business needs

A master plumber licence belongs to a person.

It certifies that the individual cleared the state's top individual exam — or its equivalent — and may perform and supervise plumbing work at the highest individual rung.

A plumbing contractor licence belongs to the business: it is the permission to bid, sell and contract for plumbing work as a company, and the state anchors it to a named licensed individual, the qualifier.

The qualifier's title changes by state — Florida and Tennessee call the role the qualifying agent; Arizona, Louisiana, Mississippi and New Mexico call it the qualifying party; California uses the RMO or RME; Alabama's plumbing board the Principal Master; Texas and Colorado the Responsible Master Plumber; Montana and Massachusetts the master plumber of record; New Jersey the bona fide representative; Oregon the Responsible Managing Individual; Nevada the qualifying individual; Virginia the Qualified Individual; South Carolina the Primary Qualifying Party; and DC the designated master.

The trap is assuming the two licences are the same everywhere.

In a large group of states there is no separate company licence at all — the individual master (or equivalent) licence is what lets a business contract: Georgia, Maine, Kentucky, Delaware, Montana, Wisconsin, Texas, Louisiana, New Jersey, North Dakota, Connecticut and Rhode Island, with New York City and Nebraska's city master licences working the same way.

That word equivalent matters at the edges: Connecticut has no master title, so the credential a business contracts through is its individual P-1 plumbing contractor licence, and Rhode Island gives the company a choice — a master plumber as an officer or partner, or a DLT plumbing contractor licence backed by a continuously employed master.

Where a company licence does exist, it often still needs that licensed individual behind it — which is why the master-plumber question below decides most applications.

The individual ladder itself (apprentice, journeyman, master) is its own subject: what a master plumber is covers the person-level credential, and the journeyman plumber guide covers the rung below it.

Statewide licensing splits into patterns.

A first group issues the plumbing contractor licence directly to the business — Florida (certified statewide or registered local), California (C-36), Arizona (C-37, R-37, CR-37), Michigan, Minnesota, Nevada, Utah, Ohio, Washington and others, each with its own board and its own forms.

A second group runs on the master licence instead: in the states listed just above, there is no company licence to apply for — hiring or becoming the master (or the state's equivalent top individual licence, like Connecticut's P-1) is the licensing step.

A third group licenses plumbing at the city or county level.

Kansas has no state plumbing contractor licence — licensing is local, under uniform state standards.

Missouri has no statewide plumbing or HVAC licence and leaves the trade to cities and counties; Kansas City issues Journeyman and Master Plumber certifications of its own.

Nebraska contracts through city master licences (Omaha Master Plumber; Lincoln Master Plumber Contractor).

New York's licences are local, and New York City's Master Plumber licence doubles as the business licence.

Wyoming's state agency runs no plumbing licence program, so cities such as Casper license the trade.

A few states we could not pin down: for Arkansas, Maryland, Pennsylvania (outside Philadelphia and Allegheny County) and Vermont, the absence of a state-level contractor licence was not affirmatively sourced in the material we reviewed.

Ask the state board — or the county — before you assume anything there.

Licensing is often local, and rules change.

Before you bid in a new jurisdiction, confirm the current requirement with the board named in the rundown below — or with the city or county building department where licensing is local.

Job value matters in a few states, too: the Louisiana LSLBC plumbing classification and South Carolina's commercial licence switch on above $10,000, Tennessee's state contractor licence at $25,000, and Mississippi's and Arkansas's commercial contractor licences at $50,000, while North Carolina and Oklahoma (mechanical) set no dollar threshold at all.

And do not treat a small-job exemption as a safe harbour — Nevada's under-$1,000 handyman exemption excludes plumbing outright, and the FAQ below covers the traps.

In the states that issue a company licence, the answer is built into the application: somebody holding a top-level individual credential must stand behind the business.

Texas requires the business to secure a Responsible Master Plumber — a master plumber in good standing with at least $300,000 liability insurance whose licence may be used by one plumbing company only.

Colorado's plumbing contractor names a Responsible Master Plumber who is actively engaged full time and responsible for all plumbing work.

New Jersey's master plumber must hold at least 10% of the business as its bona fide representative.

Massachusetts writes the master plumber of record into the corporate articles (an LLC lists a manager; every partner in a partnership must be a master).

Minnesota requires a responsible individual holding an active master licence who works for no other plumbing contractor.

Illinois expects a licensed plumber among the sole proprietor, partners or corporate officers.

New York City goes further: the Master Plumber licensee must be an officer, partner or sole proprietor of the business, and in a corporation the licensees must hold at least 51% combined controlling interest.

A few states have no master title to staff.

Connecticut, Idaho, Indiana, Oklahoma and South Dakota top out at an individual contractor licence instead of a master licence (as of September 2026), so the contractor credential itself is the qualifier — Indiana's corporations, for example, name their responsible licensed plumbing contractor at every renewal.

South Dakota flips the staffing question: plumbers there work as employees of, or under the direction of, a licensed plumbing contractor.

Sharing one master across companies is restricted.

Georgia, North Carolina, Ohio, Idaho (plumbing), Minnesota (plumbing) and Texas (ACR and RMP) do not allow a qualifier on two companies at all; states that allow it require common ownership — Arizona 25%, California 20%, Nevada 25%, New Mexico 30%, Hawaii 51%, Kentucky 25% — Mississippi allows up to three companies, and Florida allows extra businesses at the board's discretion.

Plan for the qualifier leaving, because every state does.

Notice and replacement deadlines run from stop-work-immediately (North Carolina; New Hampshire plumbing and gas work until replaced) to 14 days (Oregon temporary RMI), 30 days (Nevada), 60 days (Florida, Louisiana LSLBC, Utah), 90 days (California, Mississippi, South Carolina, Ohio) and 3 months (Tennessee).

A few states add specific notice: Minnesota requires written notice to DLI within 15 days of losing the responsible individual, Georgia notice within 7 days, and Kentucky gives a company a 180-day interim period after a master's death — with notice within 10 days.

Treat plumbing as separately licensed until a state says otherwise.

In the states we checked, "general contractor" and "plumbing contractor" are different licences — and where they touch, the touch is a specific classification, not a general building licence.

Washington is explicit: a general contractor that wants to do plumbing work must also hold the plumbing contractor licence, with its own bond.

Hawaii is the mirror image — a plumber licence alone does not allow contracting; the C-37 contractor licence is required on top.

Minnesota draws the subcontracting line: general contractors subcontracting all plumbing to licensed firms do not need their own plumbing contractor licence.

Watch exam-reciprocity claims, too.

NASCLA's accredited exam does not replace HVAC or plumbing trade exams in the states we checked: Arizona, Louisiana, Nevada and New Mexico accept it only for general building (and electrical) classifications, NASCLA has no plumbing exam in use yet, and Tennessee accepts the NASCLA National Commercial exam for its commercial classifications only.

The overlaps that do exist are mechanical classifications, not general-builder ones: Mississippi's Mechanical major classification, Tennessee's full CMC mechanical classification and New Mexico's MM-98 cover plumbing, South Carolina puts Plumbing (PB) inside its Mechanical Contractors classification, and Alaska's Mechanical Administrator licence family spans plumbing and heating/process-piping categories.

South Carolina adds one broader route: a residential builder licensed by exam may perform residential specialty work — including plumbing — without a separate specialty licence.

Bonds are the commonest financial condition, and the amounts are all over the board: Washington's plumbing contractor licence requires a $6,000 bond, Minnesota's a $25,000 surety bond, Illinois plumbing contractors file a $20,000 indemnification bond or letter of credit, Oklahoma's keep a $5,000 bond, DC requires $5,000 bonds from both the company and its designated master, New Jersey master plumbers file a $3,000 surety bond, and Idaho's plumbing contractors post a $2,000 compliance bond.

Insurance minimums vary just as widely: Kentucky expects at least $250,000 general liability behind a master-plumber business; Washington pairs its bond with $250,000 liability insurance; Texas's Responsible Master Plumber designation requires proof of $300,000 commercial liability insurance; Ohio's licence runs on $500,000 liability insurance; Louisiana employing entities carry at least $500,000 aggregate general liability and property damage cover; Philadelphia master plumbers carry $500,000 general liability plus $300,000 auto liability; New York City's master plumber businesses carry at least $1,000,000 per occurrence; and Maryland's master plumbers carry at least $400,000 per occurrence — $300,000 general liability plus $100,000 property damage, with no umbrella policies accepted.

Exams usually pair a trade portion with a business-and-law portion.

North Carolina's plumbing contractor exam is a 4-hour technical plus a 1.5-hour Business and Law exam; New Mexico's MM-1 plumbing contractor exam runs 100 questions in 250 minutes with a 75% pass mark; Oklahoma requires both the business/law and trade portions; DC requires no exam for the contractor licence itself.

Who delivers the exams varies by state: PSI runs plumbing licensing exams in California, Colorado (plumbing), Louisiana (LSLBC), Maryland, Massachusetts (plumbing), Michigan, Mississippi, Ohio, South Carolina and Washington (plumbing); Prov delivers them in Indiana (plumbing), New Hampshire (plumbing), Tennessee (contractor exams from July 1, 2026, and the LLP), Utah, Vermont (ICC exams) and West Virginia; Pearson VUE runs the Florida CILB and the Texas TSBPE written exams; IAPMO runs Montana's plumbing exam; and Minnesota's DLI and New York City's DOB run their own.

Renewal tracks whatever the state issued.

Company registrations and licences renew on the board's cycle: Illinois plumbing contractor registrations expire at the end of September each year; Michigan plumbing contractor licences renew every three years by April 30 at $300; Minnesota's licence runs to December 31 of odd-numbered years at $188; Alabama's PGFB registration renews annually at $25; and Texas's Responsible Master Plumber designation renews at $300 a year (TSBPE, as of September 2026).

Where the master licence is the business licence, renewal means keeping the master's own credential current — it is the licence the business lives through.

Plumber licence renewal is annual in Alabama, Arkansas, Connecticut, Illinois, Kentucky, Louisiana, Montana, North Carolina, North Dakota, Oklahoma, South Dakota and Texas; every two years in Colorado, Delaware, DC, Georgia, Indiana, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, Rhode Island, Vermont and Virginia; and every three years in Hawaii, Idaho, Iowa and Washington (Michigan: journey annual, master 3-year).

Continuing education rides along on the individual licence where it applies: plumber CE ranges from none (Maryland, North Carolina, Michigan outside code-update cycles) to 24 hours (Oregon; Washington per three-year cycle; Wisconsin).

Renewal is also when the qualifier question bites: a lapse in the master's licence is a lapse in the company's authority to contract, and the departure deadlines in the master-plumber section above are the ones that keep you legal through a transition.

Once the licence side is current, the staffing side starts — our guide to hiring HVAC and plumbing techs covers sourcing, pay and screening.

The rundown below compresses each jurisdiction's plumbing-contractor requirement into one line, alphabetical, with the issuing authority named.

Treat it as the map, not the territory: fees, forms and thresholds move, and each board's own page is the binding version.

Alabama — no separate contractor exam: the company registers with the Board of Plumbers and Gas Fitters before bidding or working and designates a Principal Master, a master plumber who must be an active employee of the business.

Alaska — a plumbing contractor is a registered Mechanical Contractor with a Mechanical Administrator certificated in the plumbing category; the state issues no separate plumbing contractor licence.

Arizona — the Registrar of Contractors licenses the company in the C-37 (commercial), R-37 or R-37R (residential) or CR-37 (dual) plumbing classifications.

Arkansas — we could not confirm a separate state plumbing-contractor licence: plumbing appears to run under a master plumber licence, with Contractors Licensing Board licensing by project size — check with the Arkansas Department of Health and the Contractors Licensing Board.

California — the Contractors State License Board issues the C-36 Plumbing Contractor classification, covering safe water supply and fluid-waste disposal in all structures and fixed works.

Colorado — plumbing businesses register as a Plumbing Contractor with the State Plumbing Board and name a Responsible Master Plumber who is actively engaged full time and responsible for all plumbing work.

Connecticut — the P-1 Unlimited Plumbing Contractor licence is held by an individual (the state tops out at a contractor licence, with no separate company licence), and requires two years as an unlimited licensed journeyperson, or equivalent experience and training, plus the exam.

Delaware — no separate contractor licence exists: the master plumber licence is the practice licence, and the business's workers operate under a master it employs.

District of Columbia — a plumbing and gasfitting contractor licence from DLCP requires a company in good standing, a designated DC-licensed master who accepts the designation online, $5,000 bonds from both company and master — and no exam.

Florida — the CILB plumbing contractor licence is unlimited in the trade and comes certified (statewide) or registered (local), with the trade-knowledge exam given on paper at scheduled sessions.

Georgia — no separate contractor licence: a company may do plumbing only with a Master Plumber Class I or II regularly connected with it full-time.

Hawaii — plumbing contractors hold the C-37 specialty contractor licence and its sub-classes, because a plumber licence alone does not allow contracting.

Idaho — the plumbing contractor must already hold a journeyman certificate, pass the contractor exam and post a $2,000 compliance bond, and may represent only one person or business at a time.

Illinois — anyone plumbing for another person registers annually with IDPH; the registration requires a licensed plumber as an owner, partner or corporate officer, plus liability cover and a $20,000 indemnification bond — and Chicago adds its own city plumbing contractor licence on top.

Indiana — the Plumbing Commission licenses contractors after four years of apprenticeship (a licence from another state, or four years in the business under a licensed contractor, also qualify) plus the exam, and corporations add a Plumbing Corporation licence naming their responsible licensed plumbing contractor.

Iowa — the Plumbing and Mechanical Systems Board licenses plumbing contractors under the same master-of-record, insurance and bond rules as HVAC contractors.

Kansas — no state plumbing contractor licence: licensing is local, under uniform state standards, with designated ICC, IAPMO or Prometric exams.

Kentucky — no separate plumbing contractor licence: the business operates under an active master plumber licence and carries at least $250,000 general liability insurance.

Louisiana — the business is an employing entity under a designated active Master Plumber (one entity per master), and plumbing jobs over $10,000 also need the LSLBC Plumbing classification, which the master licence satisfies without a separate trade exam.

Maine — the Master Plumber licence is defined as the licence to engage in the business of installing plumbing; no separate contractor licence exists.

Maryland — the board licenses individuals, and we did not confirm a separate company licence: businesses operate under an individually licensed, insured master plumber — verify with the Maryland State Board of Plumbing.

Massachusetts — the state issues a plumbing business licence, with the master plumber of record listed as a corporate officer (an LLC lists a manager, and every partner in a partnership must hold a master licence).

Michigan — the Plumbing Contractor licence requires the applicant to hold a master plumber licence or employ a master as representative, plus an exam, and only a sole proprietor, partner, corporate officer or LLC member may apply.

Minnesota — a plumbing contractor licence from DLI (a restricted licence covers towns under 5,000) requires a responsible master who serves no other contractor, a $25,000 surety bond and liability insurance.

Mississippi — the State Board of Contractors licenses commercial plumbing as a tested specialty classification, or the business qualifies under the Mechanical major classification that spans plumbing.

Missouri — there is no statewide plumbing or HVAC licence: cities and counties license the trade, and Kansas City issues Journeyman and Master Plumber certifications.

Montana — only a licensed master may plan, estimate, bid, contract and pull permits, and the business files a master plumber of record on a $50 form.

Nebraska — no state plumbing contractor licence: contracting runs on city master licences (Omaha Master Plumber; Lincoln Master Plumber Contractor), and Omaha masters carry a $10,000 bond and $1,000,000 insurance.

Nevada — the State Contractors Board licenses plumbing statewide under C-1 Plumbing and Heating, with C-1d as the plumbing-only sub-classification.

New Hampshire — no separate plumbing-contractor class: the business needs a Mechanical Business Entity licence with a New Hampshire master plumber as an officer or responsible managing employee.

New Jersey — the plumbing contractor must have a licensed master plumber as its bona fide representative, holding at least 10% of the business.

New Mexico — the plumbing contractor class is MM-1 and asks four years of experience; natural gas piping is the separate MM-2 classification.

New York — licences are local, and in New York City the Master Plumber licence is itself the business licence, held by an officer, partner or sole proprietor with a zoning-compliant NYC place of business.

North Carolina — plumbing contractors are licensed by exam: a 4-hour technical exam plus a 1.5-hour Business and Law exam, with the restricted limited class starting at 9 months (1,500 hours) of experience.

North Dakota — no separate plumbing-contractor licence: a licensed master plumber must be in charge wherever a public water or sewer system exists, and jobs over $4,000 also need the Secretary of State contractor licence.

Ohio — the Construction Industry Licensing Board licenses plumbing contractors with five years of trade experience, trade and business-and-law exams at 70%, and $500,000 liability insurance.

Oklahoma — the Construction Industries Board licenses plumbing contractors after the journeyman requirements plus one more year and both exam portions, and active licensees keep a $5,000 bond and $50,000 general liability insurance.

Oregon — plumbing businesses need the Building Codes Division's Plumbing Business licence plus a Construction Contractors Board licence with its bond and insurance.

Pennsylvania — we did not confirm a statewide plumbing contractor licence: Philadelphia requires a licensed master plumber carrying $500,000 general liability and $300,000 auto insurance, and outside Philadelphia and Allegheny County licensing is municipal — verify locally.

Rhode Island — the company either keeps a licensed master plumber as an officer or partner continuously supervising the work or holds a DLT plumbing contractor licence while continuously employing a master, plus registration with the Contractors' Registration and Licensing Board at $500,000 liability insurance.

South Carolina — commercial plumbing contractors need the CLB mechanical contractor licence with the Plumbing (PB) subclassification, and a residential builder licensed by exam may perform residential plumbing without a separate specialty licence.

South Dakota — the State Plumbing Commission licenses contractors after six years of experience at 1,900-plus hours a year (at least two of them as a contractor or plumber) and the exam, and plumbers work under a licensed plumbing contractor.

Tennessee — the Board for Licensing Contractors requires a state contractor licence for plumbing jobs of $25,000 or more (the CMC-A Plumbing and Gas Piping classification), and below that only the Limited Licensed Plumber applies, in state-inspected areas.

Texas — no separate plumbing-contractor licence: the business secures a Responsible Master Plumber, a master plumber with $300,000 liability insurance whose licence serves one plumbing company only.

Utah — the P200 General or P201 Residential plumbing contractor classification requires the Business and Law exam plus a master-plumber-level qualifier.

Vermont — we did not confirm a separate contractor licence: plumbing must be done by licensed individuals, a specialty plumbing business may employ only licensees in its specialty, and employing unlicensed workers risks fines up to $1,000 per offence — verify with the Office of Professional Regulation.

Virginia — plumbing contractors use the PLB classification and name a qualified individual holding a Master plumber tradesman licence.

Washington — since July 2021 a separate L&I Plumbing Contractor licence is required to advertise, bid or perform plumbing work, with a $6,000 bond, $250,000 liability insurance and an assigned designated plumber; a general contractor that self-performs plumbing needs it too.

West Virginia — the plumbing contractor licence (residential jobs $5,000-plus, commercial $25,000-plus) requires the master plumber or plumbing exam plus the West Virginia Business and Law exam.

Wisconsin — no company licence exists: licences go to individuals only, a master plumber must be in charge of every installation, and a business may advertise as a plumbing contractor only if it is or employs a licensed master.

Wyoming — the state runs no plumbing licence program, so cities license the trade; Casper's Plumbing Contractor licence requires the business to have or employ a full-time licensed master plumber.

Before you rely on any line above, confirm it with the issuing board — or with the city or county where licensing is local.

Fees, thresholds and forms move; the board's current page is the binding version.

This page is employer career and business information, not legal advice. Confirm licensing requirements with the board named for your state, or an attorney licensed there.