License or registration required; exemptions
Wis. Stat. § 145.06
in effect(1)
(a) No person may engage in or work at plumbing in the state unless licensed to do so by the department. A master plumber may work as a journeyman. No person may act as a plumbing apprentice or pipe layer unless registered with the department.
(b) No public utility shall engage in or perform plumbing unless exempted by sub. (4).
(2) No person shall install plumbing unless at all times a licensed master plumber is in charge, who shall be responsible for proper installation. Licenses shall be issued only to individuals and no license shall be issued to or in the name of any firm or corporation. No such license shall be transferable. It is unlawful for any licensed master plumber to allow the use of his or her license, directly or indirectly, for the purpose of obtaining local permits for others or to allow the use of his or her license by others to install plumbing work.
(3) Each member or employee of a partnership or limited liability company or each officer or employee of a corporation engaging in the business of superintending plumbing installations shall be required to apply for and obtain a master plumber’s license before engaging in the work of superintending plumbing installations.
(3m) No person may test the performance of cross-connection control devices when the test is required by the department unless he or she is registered with the department as a cross-connection control tester.
(4) This section shall not apply to:
(a) Plumbing work done by a property owner in a one-family building owned and occupied by him or her as his or her home or farm building, except where such license is required by local ordinance.
(b) Plumbing from the private water supply pump to and including the initial pressure tank and connection to an existing water distribution system, when installed by persons licensed under ch. 280.
(c) Installation of sewer and water service piping from the main to the property lot line, when installed by authorized municipal utility employees or sewer and water utility installers under a contract with a municipality.
(d) Making minor repairs to faucets, valves, pipes or appliances, repair or replacement of electrical or gas energy or other automatic valves or control devices or removing of stoppages in waste or drainage pipes.
(e) Installation of sewer and water mains, when installed by sewer and water utility contractors and their employees.
(f) Installation, repair or replacement of water service piping, from the property line to the meter, including meter installation, to service any building or structure or proposed building or structure when such installation, repair or replacement is accomplished by employees of a public municipal water utility, providing such utility regularly has engaged in such installation, repair or replacement for at least 5 years prior to January 1, 1964.
Source: WI Statutes (Official Site)URL: https://docs.legis.wisconsin.gov/document/statutes/145.06Fetched: 10/7/2026