How to Start a Plumbing Business in Minnesota: Plumbing Contractor License, Master Plumber and the 5,000-Population Rule

If you want to run a plumbing company in Minnesota, the license question comes before everything else. Minnesota has no general statewide business license, so no single card lets you operate. Plumbing is licensed by trade, and the Minnesota Department of Labor and Industry (DLI) handles plumbing licensing. The license you need depends on where you work, how much experience you have, and whether your company will contract the work itself. This guide covers the path to a plumbing contractor license, the population rule that decides between a full and a restricted license, and the business paperwork behind it.

Disclaimer: This article is informational content, not legal or tax advice. Licensing rules, bond terms and fees change, so confirm every figure with the named agency before you pay or sign anything. For a complex setup, such as a company with several owners or one that also does pipe-laying or septic work, talk with a qualified attorney or CPA.

Materials and Documents You Need Before You Apply

Gather these items before you open a DLI application. Missing one usually stops the process until you resubmit.

• Documented experience: four years of plumbing work for a journeyworker license, or a registered apprenticeship record.
• A master plumber license for the person who will serve as your responsible individual.
• A $25,000 surety bond from a bonding company.
• Liability insurance at or above the minimums in Step 5, plus proof of workers' compensation coverage.
• A business entity filed with the Minnesota Secretary of State, such as an LLC filed with Articles of Organization.
• A Minnesota street address for your registered office. A PO box alone is not accepted.
• Payment for the $188 contractor license fee, plus the exam and license fees for any master plumber license you still need.
• A list of the cities and counties where you plan to work, since local permits may apply on top of the state license.

Step 1: Understand the License Levels

Plumbing in Minnesota uses a ladder of licenses. A journeyworker license is the first step for an individual. A master plumber license is the next step, and it is the one that qualifies a person to act as responsible individual for a contractor. The plumbing contractor license is the business license that lets a company contract plumbing work.

Two specialty categories sit beside the main ladder. A pipe-layer-only contractor works under a separate $25,000 bond filed with DLI. Septic system installers are not licensed by DLI at all. They are licensed by the Minnesota Pollution Control Agency (MPCA), so do not apply to DLI for septic work. If your business will do both plumbing and septic, you need to deal with two agencies.

Step 2: Earn Your Journeyworker and Master Plumber Licenses

Start with experience. To qualify for a journeyworker license, you need four years of plumbing work or a registered apprenticeship. Keep dated employer letters, job logs or apprenticeship records. DLI asks for proof, and a reconstructed work history is much harder to defend than records you kept as you went.

To qualify for a master plumber license, you must first work at least one year as a journeyworker. Then you pass the $50 master plumber exam and pay the $80 base license fee. The statute also adds a board fee on top of the base fee. Ask DLI for the current board fee amount before you budget for the license, because it is not a settled figure in this guide.

Once licensed, you must keep up your continuing education. Minnesota requires 16 hours every two years, and 8 of those hours must be on the plumbing code. On renewal, expect a $5 continuing education fee. Keep certificates for every course, because an audit depends on them.

Step 3: Choose Between a Full and a Restricted Contractor License

This is the step that decides where you can work. Minnesota requires a plumbing contractor license to contract plumbing work in communities with a population over 5,000. A restricted license covers only communities under 5,000.

In practice, check the population of every community where you plan to bid or perform work, and confirm with DLI how it determines the population for a particular city or township. If you bid a job in a community over 5,000 with only a restricted license, you are working outside your license. A restricted license can be a sensible starting point for a business that serves small towns, but it does not let you take jobs in larger communities.

The contractor license fee is $188 for the initial license and the same $188 for renewal. Contractor licenses expire on December 31 of odd-numbered years. Ask DLI how the first term is calculated based on your application date, because the length of your first term depends on when you apply.

Step 4: Name a Responsible Individual Who Qualifies

Every plumbing contractor needs a responsible individual. That person must hold an active master plumber license and must be one of the following:

• an owner of the company,
• an officer of the company,
• a member of the company, or
• a W-2 employee who does not work for another plumbing contractor.

The responsible individual is the person DLI holds accountable for the company's plumbing work, so choose carefully. A master plumber who is a 1099 subcontractor does not qualify under this rule, and neither does one who works for another licensed contractor. If your responsible individual leaves, plan for a replacement before the company keeps doing contract work.

Step 5: Get the Surety Bond and Insurance

The contractor license requires a $25,000 surety bond. A surety bond is a guarantee that backs your work, and the bonding company charges a premium for it. The premium is set by the bonding company, so request quotes from more than one bonding company before you commit.

You also need liability insurance at the following minimums:

Coverage	Minimum
Liability per person	$50,000
Liability per occurrence	$100,000
Property damage	$10,000

Finally, you must provide proof of workers' compensation coverage. Ask your insurance agent to issue certificates in the form DLI accepts, and confirm that form with DLI before you submit. Do not let the bond or the insurance lapse during the license term, because a gap can put the license at risk.

Step 6: Form the Business Entity With the Secretary of State

Plumbing licensing and business formation are separate processes. The license is issued by DLI, and the entity is filed with the Minnesota Secretary of State (SOS). Filing an entity with the SOS is a filing, not a license. Most plumbing owners choose an LLC, so this guide uses that example.

To form an LLC, file Articles of Organization under Minnesota Statutes, Chapter 322C. The fee is $155 online or in person, which is the expedited option, or $135 by mail, which is not expedited. The SOS does not publish a guaranteed turnaround in business days, so check the current processing guidance before you schedule your first bid.

Follow these naming and address rules when you file:

• The name must include the words "limited liability company" or the abbreviation "LLC."
• The name may not include "corporation" or "incorporated" or their abbreviations.
• The name must be distinguishable on the SOS records from every domestic LLC, LLP, corporation and limited partnership already on file or reserved in Minnesota.
• The registered office must be a Minnesota street address. It does not have to match your principal place of business.

An LLC does not need to publish a notice, but a business that operates under a name other than its legal name does. That requires a Certificate of Assumed Name filed with the SOS under Chapter 333. It costs $50 online or in person or $30 by mail. After filing, the certificate must be published for two consecutive issues in the legal notices section of a qualified legal newspaper in the county of your principal place of business, and failure to publish may make the certificate invalid. Renew it annually at no charge. File through the SOS assumed name page.

Use Business Filings Online to file the Articles of Organization and to search the SOS business records for name availability.

Step 7: Register for Taxes and Check Local Rules

Before you make any taxable sales, register with the Minnesota Department of Revenue for a Minnesota Tax ID and a Sales and Use Tax account. The state sales tax rate is 6.875 percent, and local taxes are added on top of that. Registration with the Department of Revenue is a tax registration, not a license, so it does not replace your DLI license. Confirm with the Department of Revenue whether the services you plan to sell are subject to sales tax, because that depends on the type of charge.

Minnesota has 87 counties, about 853 cities and about 1,780 townships. Local governments can add their own requirements on top of the state license. Minneapolis and St. Paul license by category, and neither issues a general business license. Before you bid a job, check the permit and license rules for the city, township or county where the work happens. A state license does not replace a local permit.

To search for licenses by trade or agency, use the state's central lookup at License Minnesota. For the plumbing license itself, go to the Department of Labor and Industry.

Step 8: Set Up Your Renewal Calendar

Your business has at least two deadlines, and they are not the same. Put both on a shared calendar with reminders at least 60 days before each date.

• Plumbing contractor license: expires December 31 of odd-numbered years. Renewal requires the $188 fee and continuing education records for the responsible individual.
• LLC Annual Renewal: due December 31 every calendar year. The fee is $0 if the entity is active and in good standing. Missing the date can terminate the LLC without further notice, and reinstatement costs $65 by mail or $85 online or in person.

Because the LLC renewal is free, it is easy to forget. A forgotten $0 renewal can still cost you the entity.

Fees and Costs at a Glance

Item	Cost	Notes
LLC Articles of Organization	$155 online or in person; $135 by mail	Expedited only when filed online or in person
LLC Annual Renewal	$0	Due December 31 every year
LLC reinstatement	$65 by mail; $85 online or in person	Applies only after a missed renewal
Certificate of Assumed Name	$50 online or in person; $30 by mail	Requires newspaper publication; renewed annually at no charge
Plumbing contractor license, initial and renewal	$188	Expires December 31 of odd-numbered years
Master plumber exam	$50	Requires one year as a journeyworker first
Master plumber base license fee	$80	A board fee is added; confirm the amount with DLI
Continuing education fee on renewal	$5	16 hours every two years, 8 on code
Contractor surety bond	$25,000 bond	Premium is set by the bonding company
Pipe-layer-only contractor bond	$25,000 bond filed with DLI	2026 to 2028 forms; confirm the filing fee with DLI
State sales tax	6.875 percent	Local taxes are added on top

Expected Results

If your experience records, responsible individual, bond, insurance and entity filing are all in order before you apply, the application process is more likely to move without rework. Applications with gaps tend to stall while you collect missing documents. DLI processing time is not a figure this guide can confirm, so check DLI's current guidance and plan your first bids around it.

Once licensed, you may be able to bid contract plumbing work in any community that matches your license class. A full contractor license is the class that covers communities over 5,000. A restricted license may limit you to communities under 5,000. Local permits can still apply, so a license class does not guarantee that a particular job is approved.

Common Mistakes to Avoid

• Bidding a job in a community over 5,000 on a restricted license. Check the population of every job site before you quote it.
• Naming a responsible individual who does not qualify. A 1099 master plumber or one who works for another contractor does not meet the rule.
• Letting the bond or insurance lapse. A gap in either can put the license at risk.
• Using "corporation" or "incorporated" in an LLC name. The SOS will not accept the name.
• Treating the LLC renewal as optional because it costs $0. Missing December 31 can end the entity.
• Assuming the state license covers city permits. Cities, townships and counties can add their own requirements.
• Calling the Department of Revenue registration a license. It is a tax registration. The plumbing license comes from DLI.
• Skipping the newspaper publication for an assumed name. Failure to publish may make the certificate invalid.
• Taking septic work under a DLI license. Septic installers are licensed by the MPCA.

Tips From the Filing Desk

• Start your master plumber and journeyworker paperwork early. The experience and exam steps take the longest.
• Keep one folder with every license number, bond number, insurance certificate and SOS filing receipt. Renewals go faster when the records are in one place.
• Look up each job site's population and local permit rules on the same day you quote the job.
• Use License Minnesota to check which other licenses your business may need beyond plumbing, such as a permit for a specific trade or activity.
• Ask a CPA how the entity will be taxed. An LLC taxed as a partnership or disregarded entity passes income through to owners, who pay the individual income tax of 5.35 to 9.85 percent. An LLC that files as a C corporation pays the 9.8 percent corporation franchise tax.

When to Get Professional Help

Get help from a qualified attorney or CPA if you have several owners, if you plan to do both plumbing and septic work, if you want to take pipe-laying work under a separate bond, or if you are unsure how the entity choice affects your taxes. A plumbing business can be simple to run, but the licensing, entity and tax pieces each carry their own rules, and a mistake in one can affect the others.

For the state's small business support, the Minnesota Small Business Development Center Network offers business advising that can help you sort out the business side before you file.

Disclaimer: This article is informational content, not legal or tax advice. Confirm all fees, deadlines and requirements with the Minnesota Department of Labor and Industry, the Secretary of State and the Department of Revenue before you act.