How to Start a Plumbing Business in Idaho: Journeyman and Contractor Licenses and How to Qualify

If you want to run a plumbing business in Idaho, the credential you need is not a general business license. Plumbing is regulated by the State Plumbing Board, which operates under the Idaho Division of Occupational and Professional Licenses (DOPL) and issues certificates of competency. Under Idaho Code 54-26 and the rules in IDAPA 24.39.20, plumbing work without the right certificate is unlawful. For most people building a plumbing business, the path runs in order: apprentice (if you are still training), then journeyman, then contractor. This guide walks through each step, the fees DOPL lists, and the business formation and tax steps that come after.

This is informational content, not legal or tax advice. Requirements can change, and DOPL's current forms and fee schedule control. Confirm details with DOPL and talk to a qualified attorney or CPA before you choose an entity or make tax decisions.

What You Need Before You Start

Gather these items before you file anything. Missing one of them is the most common reason applications stall.

• Your plumbing work history. You need records that show apprentice hours (8,000), or total plumbing experience (16,000), depending on the path you use. Keep dated job logs, employer letters, and timesheets.
• Proof of approved instruction. If you use the apprentice path, you need 576 hours of approved instruction in addition to the apprentice hours.
• An apprentice certificate if you are still logging hours. It costs $50 and is valid for 5 years.
• Fees for the application and certificates. DOPL lists a $22.50 application fee. Journeyman initial certificate: $29.40. Contractor initial certificate: $147. Exam fees are set by the exam vendor and DOPL, so confirm them on the DOPL plumbing page before you register.
• A $2,000 compliance bond from a surety company, required before a contractor certificate is issued. The $2,000 is the bond amount, not the premium. The premium you pay the surety is separate and is not listed in DOPL's fee schedule.
• A physical Idaho street address for your business and registered agent. P.O. boxes are not accepted for a registered agent.
• An Idaho Secretary of State account on SOSBiz (sosbiz.idaho.gov) if you plan to form an LLC or corporation.
• A decision on business structure and a name that meets Idaho's naming rules.

Step 1: Confirm Your Work Needs a Plumbing Certificate

Start by checking whether your work is covered. Idaho Code 54-2602 includes two exemptions that matter most to readers:

• Owner exemption. An owner doing plumbing work on their own single or duplex home is exempt. This covers your own residence. It does not cover work on rental property you own for other people to occupy, or on someone else's home for pay. Confirm your situation with DOPL before relying on it.
• Sewer, septic, and excavating exemption. Sewer, septic, or excavating contractors working on lines outside the building foundation walls are exempt. Work inside the foundation walls is still plumbing.

Even when a plumbing certificate is not required, local permits and inspections still apply to the work. If your business touches both exempt and covered work, treat the covered work as requiring a certificate.

Step 2: Pick the Certificate Class You Need

The State Plumbing Board issues three main classes, plus specialty classes:

• Apprentice. For people who work under a licensed plumber while logging hours and instruction. Valid for 5 years.
• Journeyman. For people who have met the hour requirements and passed the exam. Required to work as a qualified plumber. Carries a 3-year term.
• Contractor. For people who want to run the business, contract plumbing work, and be responsible for it. Requires a journeyman certificate plus a contractor exam and bond. Carries a 3-year term.
• Specialty classes. DOPL issues additional specialty certificates. Ask DOPL whether a specialty class applies to the work you plan to bid.

If you are starting from scratch, plan for the apprentice and journeyman steps first. You cannot skip to a contractor certificate without a journeyman certificate.

Step 3: Qualify for a Journeyman Certificate

DOPL lists two paths to journeyman qualification. Choose the one your records support:

1. Apprentice path: 8,000 apprentice hours and 576 hours of approved instruction, plus passing the journeyman exam.
2. Experience path: 16,000 hours of plumbing experience, plus passing the journeyman exam.

Most people who use the apprentice path log hours while holding an apprentice certificate. Ask DOPL how your hours must be documented and whether each type of work counts before you assume the hours will be accepted. Under the experience path, plan to document the work with detailed records. Vague employer letters are a common reason for delays.

Step 4: Apply for the Exam Through DOPL and PSI

DOPL handles the application, and PSI administers the exams. After DOPL approves your application, you schedule the exam through PSI. Start with the DOPL plumbing page at dopl.idaho.gov/plb to confirm the current application form, the current exam fee, and the exam scheduling steps. Do not rely on older forms or third-party sites that list outdated fees.

Study the exam content published by DOPL or PSI. If you have not taken a plumbing exam in a while, use a practice test and review the Idaho-specific code references the exam covers.

Step 5: Get Your Journeyman Certificate

After you pass the journeyman exam, pay the initial certificate fee of $29.40. The certificate has a 3-year term. The renewal fee is $21.60. Keep the certificate on file and calendar the renewal date as soon as it issues.

Step 6: Qualify for a Contractor Certificate

A contractor certificate requires three things:

1. A current journeyman certificate.
2. Passing the contractor exam, administered through PSI.
3. A $2,000 compliance bond posted with DOPL.

The initial contractor certificate costs $147 and carries a 3-year term. The renewal fee is $108. Shop for the bond early. Surety companies set premiums based on your credit and experience, and the premium you pay is not a DOPL fee. Ask the surety how the bond is filed with DOPL and whether the bond must stay in place for the life of the certificate.

Step 7: Form Your Business Entity With the Idaho Secretary of State

Forming a business entity and holding a plumbing certificate are separate steps. The Idaho Secretary of State handles entity filings, not DOPL. Confirm with DOPL how the certificate holder must be tied to your entity on any filings or contracts.

LLC. File a Certificate of Organization (Limited Liability Company). The filing fee is $100 online or $120 on paper. The name must include 'limited liability company', 'limited company', or an abbreviation such as 'LLC', 'L.L.C.', 'LC', or 'L.C.' Under Idaho Code 30-21-301, the name must be distinguishable from existing, reserved, and registered names on Secretary of State records. Entity-type words like 'LLC' do not count when testing distinguishability.

Corporation. File Articles of Incorporation (General Business). The filing fee is $100.

Processing for business filings is typically 7 to 10 days from filing. Expedited options are available. Idaho Code 30-21-214 sets a $40 surcharge for evidence of filing within 8 working hours and a $100 surcharge for same-day service on filings submitted before 1:00 p.m. Mountain time. Confirm current processing estimates on the SOSBiz processed-through date page before you pay for expedited service.

You must continuously maintain a registered agent with a physical Idaho street address. The agent can be you, if you live in Idaho and have an Idaho address, or a commercial registered agent. A DBA cannot serve as your registered agent.

To reserve a name while you prepare the filing, the Secretary of State's name reservation costs $20 and lasts 120 days. Use the forms page at sos.idaho.gov/business-forms to confirm current forms.

Annual report. An annual report is required each year. It is due before the end of the month in which your certificate of organization or articles became effective, beginning one year after formation. The fee is listed as no fee.

Tax treatment. A default LLC is a pass-through entity. Members report Idaho income on their personal returns at the flat 5.3% rate. An LLC that files as a partnership or S corporation owes the $10 permanent building fund tax. An LLC taxed as a C corporation pays the 5.3% business income tax plus the $10 permanent building fund tax. Entity choice is a decision to make with a CPA.

Step 8: Register a Trade Name If You Need One

If your plumbing company will operate under a name different from your legal name or entity name, file a Certificate of Assumed Business Name, commonly called a DBA. The Idaho DBA is filed with the Idaho Secretary of State, not the county. The fee is $25 filed online or $45 on paper, which includes a $20 manual data entry surcharge. An assumed business name stays active until you cancel it and is not subject to renewal.

Step 9: Check City and County Requirements

Idaho does not have a state business license. Registering your entity is a registration, not a license. Counties do not issue a general business license. Cities are different: some require a general license or permit for businesses operating within city limits, and others license only specific activities. Do not assume your city follows either pattern. Call the city clerk in each city where you will work, and the county clerk for unincorporated areas. The Business Wizard at business.idaho.gov builds a checklist of agencies and permits for a specific activity, which is a useful starting point. Local plumbing permits and inspections apply regardless of the business license answer.

Step 10: Register for Idaho Taxes

Register with the Idaho State Tax Commission at tax.idaho.gov. Idaho's personal income tax is a flat 5.3%. The state sales tax rate is 6%, and Idaho has no local sales tax outside voter-approved resort cities. If you will collect sales tax on taxable sales, apply for a sales tax permit through the Idaho Business Registration page at tax.idaho.gov/ibr. Whether your plumbing labor, parts, or fixtures are taxable depends on how you structure invoices, so confirm that treatment with the Tax Commission or a CPA before you send your first bid.

Step 11: Build a Renewal Calendar

Your plumbing certificate and your entity filings run on separate schedules. Put all of them in one calendar:

• Journeyman and contractor certificate renewals, currently listed as 3-year terms.
• Apprentice certificate, valid 5 years.
• Compliance bond, which must remain in place for a contractor certificate.
• LLC or corporation annual report, due every year.
• DBA, which does not renew but should be canceled if you stop using it.

DOPL is moving its boards to 2-year renewal cycles. Check dopl.idaho.gov/plb for the current renewal cycle and fee before you calendar a date. Do not rely on a renewal date printed on an older certificate.

Tips for a Smoother Application

• Start the hour records now. A dated log kept from day one is far easier to defend than a reconstructed one.
• Confirm each fee on the agency page. Fees and forms change. Confirm on dopl.idaho.gov/plb and sos.idaho.gov before you pay.
• Ask about specialty classes early. If your work includes a specialty area, confirm whether it needs its own certificate before you bid.
• Get the bond quote before you plan your launch date. The bond is often the step that takes the longest to arrange.
• Use a Secretary of State name check before you order signs or a website. A name that is not distinguishable can be rejected at filing.

Common Mistakes to Avoid

• Treating the owner exemption as a general permission. It covers your own single or duplex home, not work for other people or on rental property you own for others to occupy.
• Forming an LLC before confirming the certificate path. The entity filing does not qualify you to do plumbing work. Check the certificate requirements first.
• Assuming a county license is required. Counties do not issue a general business license. Check the city, and check whether any specific activity needs its own permit.
• Filing a DBA with the county. The Idaho DBA is filed with the Secretary of State.
• Using a P.O. box for the registered agent. Idaho requires a physical street address.
• Missing the annual report. It is required every year, even though the fee is listed as no fee.
• Calling the DOPL renewal date a guess. Check the current cycle on the DOPL page instead of counting from the issue date on an older certificate.

Fee Summary

Item	Amount	Notes
DOPL application	$22.50	Listed by DOPL
Apprentice certificate	$50	5-year term
Journeyman certificate, initial	$29.40	3-year term
Journeyman certificate, renewal	$21.60	Confirm current cycle
Contractor certificate, initial	$147	3-year term
Contractor certificate, renewal	$108	Confirm current cycle
Compliance bond	$2,000 bond amount	Premium is set by the surety
LLC Certificate of Organization	$100 online, $120 paper	Secretary of State
Corporation Articles of Incorporation	$100	Secretary of State
Name reservation	$20	Lasts 120 days
Assumed business name (DBA)	$25 online, $45 paper	Not subject to renewal
Annual report	No fee	Required every year

Exam fees are not listed in this summary. Confirm them through DOPL and PSI.

Expected Results

If you complete the steps in order and keep clean records, you should be in a position to operate legally as a contractor once your certificate issues. Timing depends on how quickly your hour documentation is accepted, how soon you can schedule the exam, how long the bond takes to arrange, and how long the Secretary of State takes to process your entity filing. Many applicants may find that the bond and the exam scheduling take longer than the paperwork. Plan a buffer of several weeks before you bid your first job, and confirm current processing estimates with each agency.

Holding a contractor certificate may help you pull permits and take on residential and commercial plumbing work, but local permit rules still apply. Expect that each city or county may have its own permit process, inspection schedule, and forms.

Where to Get Help

• DOPL, State Plumbing Board: (208) 334-3233, dopl.idaho.gov/plb
• Idaho Secretary of State: sos.idaho.gov, business search at sosbiz.idaho.gov/search/business
• Idaho State Tax Commission: tax.idaho.gov
• Idaho Small Business Development Center: idahosbdc.org, free advising for new business owners
• SBA Boise District: sba.gov/district/boise

Disclaimer: This article is informational content, not legal or tax advice. Plumbing certificate requirements, fees, and filing rules are set by the State Plumbing Board, DOPL, the Secretary of State, the State Tax Commission, and local governments, and they change. Confirm every figure on the agency page before you file. For entity choice, tax treatment, bonding, and contracts, consult a qualified attorney or CPA.