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A water conditioning system is designed to treat water to alter, modify, add or remove mineral, chemical or bacterial content, in a water distribution system. Water conditioning work includes the installation and servicing of water conditioning systems.

Water conditioning does not include:

  • a valve that allows isolation of a water conditioning installation;

  • piping greater than two-inch nominal pipe size; or

  • a direct connection without an air gap to a soil or waste pipe.

Anyone licensed by the Minnesota Department of Labor and Industry (DLI) as a plumber can perform water conditioning work in Minnesota without a separate water conditioning license.

You can perform water conditioning work in Minnesota if you are:

  • At least 18 years old or a high school graduate (or 16 years old if you are employed by a company owned by one or both of your parents).

  • Licensed with DLI or registered with DLI as a registered unlicensed plumber or registered unlicensed water conditioner.

  • A W-2 employee of a licensed plumbing or water conditioning contractor or registered plumbing employer.

  • Licensed owner or officer of a licensed plumbing or water conditioning contractor or restricted plumbing contractor.

You can perform water conditioning work without a license if:

  • You are registered with DLI as a registered unlicensed plumber or registered unlicensed water conditioner.

  • Your work falls under the scope of the work your employer is authorized to perform.

  • Your work is always directly supervised by a licensed journeyworker or master plumber or water conditioner journeyworker or master.


Registered unlicensed water conditioner

  • Apply online or submit the application forms and $14 application fee.

  • You will be assigned a registration number beginning with the letters "RW."

  • Registrations expire June 30 each year.

Registration renewal


Water conditioning journeyworker exam and license

You must pass an exam to apply for a water conditioning journeyworker license. To take the journeyworker exam, you must:

  • Have at least six months (875 hours) of practical experience performing water conditioning work as a registered unlicensed water conditioner or registered unlicensed plumber. Your work experience must include the following minimum number of hours in these areas:

    • Installation: 100 hours

    • Servicing: 200 hours

    • The remaining hours may relate to any other aspect of water conditioning work; or

  • Have water conditioning work experience outside of Minnesota, which DLI has determined is substantially equivalent to work performed while in the employ of a licensed contractor in Minnesota, or 

  • Have water conditioning work experience in the United States military, which DLI determines is equivalent to work performed in the employ of a licensed water conditioning contractor. Military work experience must be certified by the military.

Credit for work experience will be granted if you:

  • Were registered with DLI as a registered unlicensed water conditioner while performing water conditioning work in Minnesota. 

  • Were employed by a company that was licensed by DLI as a plumbing contractor or water conditioning contractor, or registered with DLI as a registered plumbing employer.

  • Have sufficient work experience from another state as described above and certified by the employer in the other state(s).

The exam

If you do not pass the exam you must wait 30 days before reapplying. When you pass the exam you will receive instructions on how to pay for your license.

License renewal

Licenses expire December 31 of the year after the license is first issued, and then every two years from then on. To renew your license:

  • Complete four hours of DLI-approved continuing education (at least two hours must pertain to the State Plumbing Code and two must pertain to technical topics related to water conditioning).

  • Submit the $48 renewal fee. A late fee of $17.50 is added for late renewals.

  • Renew online or submit a paper application.


Water conditioning master exam and license

You must pass an exam to apply for a water conditioning master license. To qualify to take the water conditioning master license exam, you must:

  • Have been licensed as a water conditioning journeyworker for at least one year, or

  • Have at least one year of practical experience as a registered unlicensed water conditioner with the following minimum number of hours in these areas:

    • Installation: 200 hours

    • Servicing: 300 hours

    • Planning: 250 hours

    • Supervising: 250 hours

    • The remaining hours may relate to any other aspect of water conditioning.

The exam

If you do not pass the exam you must wait 30 days before reapplying. When you pass the exam you will receive instructions on how to pay for your license.

License renewal

Master water conditioner licenses expire December 31 of the year after the year in which the license was first issued, and every two years from then on. To renew your license:

  • Complete four hours of DLI-approved continuing education (at least two hours must pertain to the State Plumbing Code and two must pertain to technical topics related to water conditioning).

  • Submit the $88 renewal fee. A late fee of $37.50 is added for late renewals.

  • Renew online or submit a paper application.


Questions?

Contact us at dli.license@state.mn.us or 651-284-5031.