Missouri · Plumbing licensing · official-source guide
Missouri does not license plumbers at state level. The Division of Professional Registration has no plumbing board. RSMo Chapter 341 puts a board of examiners in every city of fifteen thousand or more and a plumbing department in first classification counties that adopt it. Kansas City and St. Louis, both charter cities, run their own licenses instead.
State-level license
No — see local details
Public lookup
Not published
Verified against agency sources on 2026-09-11. Rules and fees change; confirm with the named authority before relying on this guide.
The Missouri Division of Professional Registration lists every profession the state licenses. That list runs from Accountancy through Veterinary and includes Electrical Contractors, but it contains no plumbing board and no plumber entry. Electricians got a state licensing board in Missouri. Plumbers did not. What exists instead is RSMo Chapter 341, titled Plumbers and Plumbing, and the chapter never creates a state agency. It creates local machinery in two separate blocks. Sections 341.010 to 341.080 apply to cities and towns of fifteen thousand or more inhabitants and put a board of examiners of plumbers inside each of those cities. Sections 341.090 to 341.220 carry the title Uniform Plumbing Code and apply to counties of the first classification only, and then only after the county commission makes a finding on its records that the sections are necessary for public health and safety in that county. So the practical answer for a contractor is that Missouri regulates the person and the company at city and county level, and the credential you need depends on where the pipe is. There is no statewide plumbing examination, no state plumber roster, no state continuing education requirement for plumbers, and no state reciprocity agreement, because there is no state board to enter into one.
Sourcespr.mo.gov 1revisor.mo.gov 2revisor.mo.gov 3revisor.mo.gov 4
Section 341.010 states that any person engaging or working at the business of plumbing in cities or towns of fifteen thousand or more inhabitants, either as master plumber or journeyman plumber, shall first receive a certificate under sections 341.010 to 341.080. Section 341.020 adds the employing plumber as a third category and requires the applicant to pass an examination the board directs, which may be in whole or in part in writing, of practical and elementary character but strict enough to test the applicant. Section 341.040 builds the board itself. Every city of fifteen thousand or more has a board of examiners of plumbers of three members: the chairman of the city board of health as ex officio chairman, a master plumber, and a journeyman plumber. The mayor appoints the second and third members, the council approves them, they serve one year terms, and each must have at least six years of practical experience as a plumber and be actively working in the plumbing business at appointment. Section 341.070 requires the same cities to create an office of plumbing inspector by ordinance, with a holder who has not less than six years of practical plumbing experience and no direct or indirect interest in any plumbing firm. Section 341.060 requires the city to prescribe by ordinance the rules for material, construction and inspection, and to bar plumbing work without a permit.
Sourcesrevisor.mo.gov 1revisor.mo.gov 2revisor.mo.gov 3revisor.mo.gov 4revisor.mo.gov 5
This is the sentence in Missouri law worth knowing. Section 341.050 says the board of examiners shall examine applicants as to their practical knowledge of plumbing, house drainage and ventilation, and on being satisfied of competency shall issue a certificate authorizing the applicant to work as a master plumber, employing plumber or journeyman plumber. Then it says the certificate shall be valid and have force throughout the state and shall be renewable annually. A certificate issued by one Missouri city board is written by statute to carry statewide. Section 341.030 tells you where to get it: applicants apply to the board of the city where they reside, or to the board nearest their place of residence. Section 341.050 sets the fee. Five dollars for a master plumber or employing plumber certificate and one dollar for a journeyman plumber certificate, with all fees paid into the treasury of the city that issued the certificate. Those figures have stood unchanged since 1939 and cities charge their own separate license and permit fees on top. Section 341.040 caps what the two trade members of the board can be paid at no more than the amount collected for certificates. Section 341.080 sets the penalty for violating sections 341.010 to 341.080 as a misdemeanor.
Sourcesrevisor.mo.gov 1revisor.mo.gov 2revisor.mo.gov 3revisor.mo.gov 4
The revisor's own annotation under section 341.040 records the holding that matters here. In State ex rel. Sprague v. City of St. Joseph, 549 S.W.2d 873, the court held that chapter 341 is not applicable to a constitutional charter city because of Article VI, Section 22 of the Missouri Constitution. Kansas City and St. Louis are both constitutional charter cities. That is why neither of them runs the three member board of examiners that section 341.040 describes, and why their plumbing credentials look nothing like each other or like the statute. Kansas City licenses through a Permits Division under Article XII of its Building and Rehabilitation Code, splitting the credential into a personal certificate of qualification and a separate company contractor license. St. Louis runs a five member Board of Examiners of Plumbers and Drainlayers under Ordinance 71644, which issues master plumber, master drainlayer, journeyman plumber and plumbing apprentice licenses and sets its own examinations and passing grades. Section 341.210 makes the same point from the county side. Sections 341.090 to 341.220 do not limit existing municipal authority, and they do not apply inside any municipality in such a county that has provided by ordinance for the regulation of plumbing, sewer and water installations, so long as that ordinance does not conflict with the state sections.
Sourcesrevisor.mo.gov 1kcmo.gov 2stlouis-mo.gov 3revisor.mo.gov 4
Sections 341.090 to 341.220 are known by statute as the Uniform Plumbing Code and apply to counties of the first class only. Section 341.100 adds a switch. The sections take effect in a first class county only after the county commission finds on its records that they are necessary for the promotion of public health and safety in that county, and not otherwise. Where they are in force, section 341.110 creates a county department of plumbing and sewer inspection and section 341.160 creates a county board of plumbing and sewer inspection. Section 341.140 is the operative restriction. No person may cause, authorize or permit the installation, construction, alteration or repair of any sewer, sewage treatment device, plumbing or drainlaying on any building or premises except minor repairs, other than by a licensed plumber or drainlayer, and a permit must be obtained from the department before work starts and all inspection fees paid. All work must be done by or under the direction or supervision of the plumber or drainlayer named on the permit. Section 341.090 defines minor repairs narrowly: leaks in drains, pipes, traps and cocks, opening waste or supply pipes, traps or drains, and repairing broken fixtures or frozen pipes. It excludes connections to soil, supply, waste, vent or inside rain leader pipes and excludes replacing or setting any fixture.
Sourcesrevisor.mo.gov 1revisor.mo.gov 2revisor.mo.gov 3revisor.mo.gov 4
Section 341.170 sets four grades and holds them to hard ages. A master plumber applicant must be at least twenty-five years of age and have three years or more experience as a licensed journeyman plumber, licensed by any county or city operating under plumbing laws or regulations equal to these sections, and must be able to direct others and be skilled in planning, designing and installing plumbing and drainage. A journeyman plumber applicant must be at least twenty-one years of age and have at least five years of experience as an apprentice under the direction and supervision of a master plumber licensed under these sections or under equal laws elsewhere. A master drainlayer applicant must be at least twenty-five and have three years or more as a licensed journeyman drainlayer. Section 341.180 sets the fees and the term. Ten dollars deposited with the application for a master plumber or master drainlayer license, two dollars for a journeyman plumber or journeyman drainlayer license, a term of one year for all licenses, and renewal on application to the board with the same fee. Miss the expiration date and section 341.180 requires reexamination on the same terms as a new applicant. An applicant who fails may reapply ninety days after the date of the original application with the examination fee.
Section 341.200 puts a surety bond in front of the license. Before a license is issued to any master plumber, the applicant must file with the supervisor of the department of plumbing and sewer inspection a surety bond in the amount of two thousand dollars with one licensed corporate surety, and a master drainlayer must file the same two thousand dollar bond. The county counselor approves the bond. It is given for faithful observance of the orders and regulations adopted under these sections, indemnifies the county or any person for damage or injury from the plumber's negligence, indemnifies against failure to perform the work in a careful and workmanlike manner, and is conditioned on the principal employing licensed journeymen. Subsection 2 of section 341.200 carries two obligations a contractor trips over. Every licensed master plumber, journeyman plumber or drainlayer has the duty to show the license on demand to any inspector of the department. And it is unlawful for any person to hold himself out or to represent himself to be a licensed plumber or licensed drainlayer without first having secured a license. A drainlayer license holder may not do plumbing work or install plumbing equipment inside a building. Section 341.210 says a plumber who filed the county bond cannot be made to file a second bond with a municipality inside that county.
Missouri splits the penalty between the two halves of Chapter 341. Section 341.080 makes any violation of sections 341.010 to 341.080, the city of fifteen thousand or more block, a misdemeanor and stops there. Section 341.220 is far more specific for the first class county block. Any person, plumber or drainlayer who violates sections 341.090 to 341.220 is guilty of a misdemeanor and on conviction is subject to a fine of not less than five dollars and not more than one hundred dollars for each offense. Each day the sections are violated is a separate offense. The same section directs the prosecuting attorney to rigidly enforce the sections and requires the sheriff, constables and the police officers of every city, town and village in a covered county to make arrests for violations. Section 341.190 adds the license consequence. The county board of plumbing and sewer inspection may revoke or suspend any license it issued on satisfactory proof that the holder obtained it by fraud or misrepresentation, failed or refused to comply with the sections or the regulations after notice from the supervisor, or was convicted of violating them. A revoked or suspended license may be reinstated only after three months, by applying in the same manner as an original application, and the board's finding is reviewable by the circuit court on certiorari.
Kansas City separates the person from the company. The person earns a certificate of qualification. The company holds the contractor license. The city's published requirements for a journeyman plumber certificate ask for at least two years of experience in the installation of plumbing, verified by at least two notarized reference letters from past or present supervisors or employers under Section 18-336 of the Code of Ordinances. The applicant must be at least 21 years of age under Section 18-339 and hold a high school diploma or GED, with one additional year of experience substituting for each missing year of high school. The examination is journeyman plumbing with gas, number 30615 through Prometric or number 675 through ICC, only one test may be taken per one month period, and the passing score must be achieved within one year of the application processing date. The master plumber requirements ask for three years of full time experience at the trade of plumbing including one year as a certified journeyman plumber, two notarized letters, and the master plumbing with gas examination, number 30315, through Prometric or ICC. Both certificates carry a $60.00 nonrefundable application fee, with testing agency fees charged separately. Kansas City waives its examination for an applicant who already holds a passing score on a comparable Prometric or ICC examination.
Once a qualified individual exists, the business applies. Kansas City information bulletin IB118 lists 17 contractor license classes, plumbing among them, and prices the license at a $60.00 nonrefundable application fee plus $181.00 to issue. Renewal is quadrennial at $181.00, so the license runs four years rather than one. A certificate of qualification follows the same pattern: $60.00 to apply, no additional charge to issue for the first four years, then $181.00 to renew on the same four year cycle. Insurance is not optional for this trade. IB118 requires it for plumbing, demolition, fire protection classes I and II, residential building and sign contractors, and information bulletin IB135 states the figure as liability insurance with a minimum aggregate limit of $1,000,000.00 per occurrence under Section 18-327(b). The city must be named as an additional insured and must get 30 days notice of cancellation, or 10 days for nonpayment. Plumbing contractors also post a cash deposit. IB118 sets a $500.00 minimum cash deposit for plumbing contractors and for fire protection contractors in classes I and II, and notes that Public Works or Water Services may require additional restoration deposits of $2,500.00 or $50,000.00. The governing text is the Kansas City Building and Rehabilitation Code, Article I Section 18-14 and Article XII.
St. Louis regulates plumbing through a five member Board of Examiners of Plumbers and Drainlayers that meets monthly. The board administers licensing for master plumbers, master drainlayers, journeyman plumbers and plumbing apprentices, prescribes the administration, form and content of the licensing tests, and determines the passing grade for each category. It also hears and determines charges or complaints against plumbers and drainlayers, approves apprentice applications, adopts rules, revokes or suspends licenses, and can order systems inspected. Its authority comes from Ordinance 71644. The Building Division houses the board and takes applications at City Hall. The permit side is where the licensing rule bites for a contractor bidding work in the city. The Building Division states that plumbing permits are issued to licensed plumbing contractors who are certified by the City of Saint Louis, and that the applicant must hold a plumbing contractor's license issued by the City of St. Louis Building Division. The application fee for all plumbing permits is $30, with the balance of the permit charge set by a separate fee schedule. A license from another Missouri jurisdiction does not substitute for the city license when the work is inside city limits, because the permit is only issued to the city certified holder.
St. Louis County is the clearest working example of the first classification county scheme, and it shows how far a county can go past the statutory floor. Section 341.200 sets a two thousand dollar surety bond as the statutory minimum for a master plumber in a covered county. The county's own master plumber surety bond form, published by the Department of Transportation and Public Works under its plumbing licensing pages, requires a bond in the sum of twenty-five thousand dollars, written as $25,000.00, running to St. Louis County, Missouri, and cites Chapter 1103 SLCRO 1974 as amended. That is more than twelve times the state floor, and it is the single largest number a plumbing contractor entering the St. Louis market has to plan for. The county runs its own Board of Plumbing Examiners and its own examination application, and it publishes a declaration of license assignment process, which is the mechanism that ties a licensed master plumber to the business that will pull permits under that license. Section 341.210 gives a plumber who filed the county bond relief from a second bond demanded by a municipality inside the county, which matters in a county with dozens of incorporated cities.
Sourcesstlouiscountymo.gov 1revisor.mo.gov 2revisor.mo.gov 3
Two Missouri state agencies regulate work that plumbing contractors routinely sell, and neither cares that there is no state plumber license. The Department of Natural Resources runs backflow prevention assembly tester certification under 10 CSR 60-11.030. State regulations require all backflow prevention assemblies to be inspected and tested by certified assembly testers. To get certified you pass a written and hands on performance examination given by the American Backflow Prevention Association or by ASSE and hold certification from one of them. The written test runs about 100 questions on backflow assembly application and testing and includes Missouri specific content. Examinations are third party proctored and course instructors may not test their own students. Certification is valid for three years. The Department of Health and Senior Services registers onsite wastewater installers. Section 701.031 states that any person installing on-site sewage disposal systems shall be registered to do so by the department. The department says any individual performing a major modification, repair or new installation of an onsite wastewater treatment system must be registered with it, and issues an identification card after the required in person courses in Jefferson City. Applicants must be at least 18 years of age, and the Basic Installer course must precede the Advanced Installer course.
Sourcesdnr.mo.gov 1dnr.mo.gov 2revisor.mo.gov 3health.mo.gov 4health.mo.gov 5
Missouri does not run a state plumber title, so the language you may use follows the credential you actually hold. Section 341.020 names three categories a city board may certify: master plumber, employing plumber and journeyman plumber. Section 341.200.2 sets the hard line in covered counties. It is unlawful for any person to hold himself out or to represent himself to be a licensed plumber or licensed drainlayer without first having secured a license under sections 341.090 to 341.220. The same subsection puts a duty on the licensee to show the license on demand to any inspector of the department of plumbing and sewer inspection. A drainlayer may not do or advertise interior plumbing work, because section 341.200.2 bars a drainlayer license holder from doing plumbing work or installing plumbing equipment or facilities inside a building. Beyond the plumbing chapter, section 407.020.1 of the Merchandising Practices Act makes deception, fraud, false pretense, false promise, misrepresentation, unfair practice or the concealment, suppression or omission of any material fact unlawful in connection with the sale or advertisement of merchandise in trade or commerce in Missouri, whether it happens before, during or after the sale. Advertising a plumbing license you do not hold in the jurisdiction where you are selling the work is exposed on both statutes at once.
There is no statewide plumber lookup, because there is no state plumber license. Verification is local, and it is worth telling a customer exactly where to look. In Kansas City the licensing office is the City Planning and Development Permits Division, reachable at cdlicensing@kcmo.org, and the city publishes both the certificate of qualification holder and the contractor license through its contractor licensing program. In St. Louis the Building Division holds the records of the Board of Examiners of Plumbers and Drainlayers at City Hall. In a first classification county the record sits with the county department of plumbing and sewer inspection that issued it. Two state searches do exist for the adjacent credentials. The Department of Natural Resources publishes its list of certified backflow prevention assembly testers as an open data set, and posts the caution that the list is not an endorsement, certification or warranty of any company. The Department of Health and Senior Services publishes a Find a Professional map for registered onsite wastewater professionals. When a Missouri contractor advertises a license, ask which jurisdiction issued it and in what grade, because under section 341.050 a city issued certificate is written to have force throughout the state while a city contractor license is not.
Sourceskcmo.gov 1stlouis-mo.gov 2data.mo.gov 3experience.arcgis.com 4revisor.mo.gov 5
These are common details other guides publish about Missouri, but we could not verify them from the agency source. Confirm them directly before relying on them.
No. The Missouri Division of Professional Registration licenses Electrical Contractors but has no plumbing board and no plumber entry. RSMo Chapter 341 assigns plumber licensing to cities of fifteen thousand or more and to first classification counties.
Section 341.010 applies to cities and towns of fifteen thousand or more inhabitants. Section 341.040 requires each of those cities to seat a three member board of examiners of plumbers, and section 341.070 requires a plumbing inspector office.
Section 341.050 says the certificate shall be valid and have force throughout the state and shall be renewable annually. Charter cities such as Kansas City and St. Louis sit outside chapter 341 and issue their own separate credentials.
Section 341.050 sets five dollars for a master plumber or employing plumber certificate and one dollar for a journeyman certificate. In first classification counties section 341.180 sets ten dollars for a master license and two dollars for a journeyman license.
In a first classification county, section 341.170 requires a master plumber applicant to be at least twenty-five years of age with three years or more as a licensed journeyman plumber. A journeyman applicant must be at least twenty-one.
Section 341.200 requires a two thousand dollar surety bond in a covered first classification county. St. Louis County requires a bond in the sum of $25,000.00 running to the county under Chapter 1103 SLCRO 1974.
You earn a certificate of qualification first, then the business applies for a contractor license. The journeyman certificate needs two years of experience and two notarized references, and both certificates carry a $60.00 application fee.
Liability insurance with a minimum aggregate limit of $1,000,000.00 per occurrence under Section 18-327(b), with the city named as additional insured. Plumbing contractors also post a cash deposit of $500.00 minimum.
A five member Board of Examiners of Plumbers and Drainlayers under Ordinance 71644, housed in the Building Division. It licenses master plumbers, master drainlayers, journeyman plumbers and plumbing apprentices and sets its own tests.
No. The Building Division states plumbing permits are issued to licensed plumbing contractors certified by the City of Saint Louis and that a plumbing contractor's license from the city Building Division is required. The permit application fee is $30.
Section 341.080 makes a violation of the city sections a misdemeanor. Section 341.220 sets a fine of not less than five dollars and not more than one hundred dollars for each offense in a covered county, with each day a separate offense.
Backflow prevention assembly testers must be certified under 10 CSR 60-11.030 through ABPA or ASSE, valid three years. Anyone installing on-site sewage disposal systems must register with the Department of Health and Senior Services under section 701.031.
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