How to Start a Plumbing or HVAC Business in Delaware: Master-Only Licensing, $173 Fee, $1,500 to $6,000 Fines and No Journeyman License

Delaware's approach to plumbing and HVAC licensing is fundamentally different from most states. There is no journeyman license, no apprentice license, and no separate mechanic credential. This creates both a challenge and an opportunity for business owners: you must hold a Master license to operate, but that also means no ambiguity about who can legally lead the work. Understanding this structure upfront will shape your entire business formation strategy.

Understanding Delaware's Master-Only Licensing Structure

Delaware's Board of Plumbing, Heating, Ventilation, Air Conditioning and Refrigeration Examiners (under the Division of Professional Regulation) issues only three trade licenses: Master Plumber, Master HVACR (Heating, Ventilation, Air Conditioning, and Refrigeration), and Master Restricted HVACR. There is no separate journeyman or apprentice credential.

This does not mean you cannot hire helpers or junior technicians. Apprentices, journeymen, and mechanics can work in the trade, but they must work unlicensed and under the direct supervision of a licensed master. The master must be either the business owner or a full-time employee of the same business entity. If you want to start a plumbing or HVAC company, you or a master-licensed employee must carry the master credential. There is no workaround.

The practical effect is that every unlicensed worker must be supervised by a master who is their employer or is employed full time by the same business entity. For many small operations, this is not a problem. For larger companies, it means careful workforce planning.

Two Routes to the Master License: Out-of-State Journeyman or All-Delaware Apprenticeship

Delaware recognizes two pathways to the master license. Understanding which applies to you is the first critical step.

Route 1: Out-of-State Journeyman Certificate Plus Two Years Under a Master

If you already hold a journeyman plumber or HVAC license from another state or from a federally-recognized apprenticeship program (such as a union apprenticeship meeting Department of Labor standards), you can qualify for Delaware's master license in two years of on-the-job training under an existing Delaware master. You will still need to pass Delaware's standardized master exam and meet other application requirements, but the timeline is shorter than starting from zero.

To use this route, your out-of-state or federal credential must be documented. You will need to provide your journeyman certificate or apprenticeship completion record along with your master application.

Route 2: Seven Years Under a Delaware Master Plus Apprenticeship-Equivalency Exam

If you have no journeyman credential, you can work under a Delaware master for seven years, then take an apprenticeship-equivalency test administered by a Delaware vocational technical school. Once you pass that test and complete your master exam, you qualify for the master license.

This route is longer but fully accessible if you are starting your career in Delaware or transitioning into the trade from another field. Many people take this path: they work with an established company for seven years, build experience and reputation, then sit for the equivalency test and master exam.

Criminal-Conviction Review and EPA Certification for HVACR

All master applicants undergo a criminal-conviction review as part of the application process. A criminal conviction record for a crime that is substantially related to providing plumbing services can block licensure, but the Board can waive that after a hearing or review if it finds that granting the waiver does not create an unreasonable risk to public safety. If you have a conviction on your record, disclose it fully in your application.

If you are pursuing a Master HVACR license (not the Master Plumber credential), you must also hold EPA-approved certification for CFC (chlorofluorocarbon) handling. This certification is separate from the master license but required before the Board will issue your master credential. Ask the Board which EPA-approved certification it accepts.

Step-by-Step: Filing Your Master License Application

Step 1: Gather Your Credentials and Work Experience Documentation

Before you open the application, assemble the following materials:

• A copy of your out-of-state journeyman certificate (if using Route 1) or a formal statement of your seven years of supervised work and the name of the Delaware master under whom you worked (if using Route 2)
• For HVACR applicants, proof of EPA CFC certification
• Copies of any relevant trade certifications or additional training you have completed
• A complete list of jobs or projects you have worked on, with dates and descriptions (the Board may request this for verification)
• Your full legal name, current address, and contact information
• Any court records related to criminal convictions (if applicable)

Step 2: Complete the Master License Application

Find the master plumber or master HVACR application through the Board's website at dpr.delaware.gov/boards/plumbers/. Fill out every field accurately. Common mistakes include:

• Leaving the work history incomplete or vague
• Failing to list the supervising master's name and license number (if known)
• Not disclosing a prior conviction when one exists
• Submitting an application without a photocopy of your journeyman certificate or equivalency test results

If you are an HVACR applicant, attach your EPA CFC certification card or proof of completion.

Step 3: Pay the Application Fee and Submit

The application fee for a Master Plumber, Master HVACR, or Master Restricted HVACR license is $173 as of 2026. Fees are paid online in DELPROS (Delaware Professional Regulation Online Services) by credit or debit card; the Division does not accept cash, checks or money orders by mail, and processing fees are non-refundable.

The Board does not publish a standard processing timeline, so ask the Board how long review currently takes.

Step 4: Sit for the Master Exam

Once the Board approves your application, you will be notified of exam dates and locations. The master exam is a written, standardized examination designated by the Board. Passing the exam is required to receive your master license. Ask the Board about exam content, retake rules and fees.

Step 5: Receive Your Master License

Once you pass the exam, the Board will issue your master license. Your license is valid for two years and expires on October 31 of even-numbered years (the next expiration date is October 31, 2028).

License Renewal, Continuing Education, and Inactive Status

Every two years, before October 31, you must renew your master license. Renewal requires proof of continuing education (CE). The Board specifies the number of CE hours required; check dpr.delaware.gov/boards/plumbers/ for the current requirement and approved CE providers.

Late renewal is available up to one year after expiration, but a late fee of 50% of the renewal fee applies in addition to the renewal fee (you are told the renewal fee at the time of renewal). After the late renewal period ends, check with the Board about what is required to restore your license.

If you are not actively working in the trade but want to keep your license, you can request inactive status, which lasts up to five years. You cannot work in the trade while inactive. To reactivate, you submit an application, pay the reactivation fee and show proof of any required continuing education.

State Business License and Contractor License Requirements

Holding a master plumber or HVAC license is not the same as being licensed to do business in Delaware. You also need a Division of Revenue license for your business. For a contractor, that is the contractor license described below.

Delaware State Business License

Any person or entity conducting a trade or business in Delaware must obtain a business license from the Division of Revenue. For a contractor (which includes plumbing and HVAC), the annual fee is $75 plus a 0.6472% gross receipts tax on your receipts above the exclusion.

Apply through Delaware One Stop at onestop.delaware.gov. Licenses run through December 31, and you file and pay any gross receipts tax owed monthly or quarterly (new businesses file quarterly).

Operating without a business license is illegal and carries a fine of up to $3,000 or up to two years in prison.

Contractor License from Division of Revenue

Plumbing and HVAC are contractor trades. You must hold a contractor license from the Division of Revenue before you sign a contract. The $75 contractor license and the 0.6472% gross receipts tax described above are part of this license. The Division will not issue it until you have:

• Filed a certificate of notice issued by the Delaware Department of Labor
• Filed a certificate of insurance showing workers' compensation coverage as the state workers' compensation laws require (or a Department of Labor self-insurer certificate)
• Paid the $75 fee (confirm current details on the Division of Revenue website at revenue.delaware.gov)

The contractor license serves as your state business license for contracting work. Apply through the Division of Revenue and confirm the current process at onestop.delaware.gov.

Understanding Gross Receipts Tax: Not Sales Tax

Delaware has no sales tax. Instead, you will owe a gross receipts tax as a contractor. This tax is calculated on your total revenue (gross receipts), not on specific transactions. For contractors, the rate is 0.6472% after a $100,000 monthly exclusion ($300,000 quarterly), and you must file and pay it monthly or quarterly (new businesses file quarterly).

Here is how it works: because the first $100,000 of receipts each month is excluded ($300,000 each quarter for quarterly filers), a contractor who receives $20,000 in a month owes no gross receipts tax for that month, while a month with $150,000 in receipts is taxed at 0.6472% on the $50,000 above the exclusion. The tax is different from sales tax because it is owed by you, not collected from customers. Consult with a Delaware accountant or the Division of Revenue to set up your filing schedule correctly.

Municipal Licenses and Permits

Depending on where you operate within Delaware (which county and which city or town), you may need additional local permits and licenses. Delaware has three counties (New Castle, Kent, and Sussex) and 57 incorporated towns. Counties and municipalities may adopt their own plumbing, HVACR and fuel-gas codes (24 Del. C. 1832).

At a minimum, your customers will need to obtain plumbing or HVAC permits from their local inspection authority before any regulated work begins. You should check with the city or county where your customer is located to understand permit requirements, inspection fees, and any local contractor registration requirements.

Consequences of Unlicensed Practice

Delaware takes unlicensed plumbing and HVAC work seriously. Working as a plumber or HVAC contractor without a master license carries these penalties:

• First offense: $1,500 to $3,000 fine
• Repeat offense: $3,000 to $6,000 fine

Justice of the Peace Courts have jurisdiction over these violations (24 Del. C. 1807(d)).

Homeowner and Agricultural Exceptions

Delaware law allows homeowners to perform plumbing and HVAC work on their own residential property without a license, with two key limits: no gas piping for homeowners, and if you are a homeowner doing plumbing work, you must still apply for a permit and allow the inspection authority to inspect the work. There is also an agricultural exception for farms and agricultural operations, but a permit application is still required.

As a professional contractor, these exceptions do not apply to you. You must hold a master license.

Setting Your Business Up for Success: Tips and Common Mistakes

Tip 1: Start Your License Application Early

Do not wait until you are ready to bid on your first job. The application and exam process can take weeks or months. File your application as soon as you have your credentials in order. You can conduct business planning while waiting for approval.

Tip 2: Get Your EPA CFC Certification Before Submitting (HVACR Only)

If you are pursuing a master HVACR license, do not submit your application without proof of EPA CFC certification. The Board will not issue your license without it, and delays in getting certified will delay your entire application.

Tip 3: Set Up Your Accounting and Tax Filing from Day One

Delaware's gross receipts tax is easy to overlook because it is not visible at the point of sale. Open a separate business bank account, track every dollar of revenue, and set aside money monthly for the gross receipts tax. Many new contractors underestimate this expense and end up short when the tax bill comes due.

Common Mistake 1: Confusing the Master License with the Business License

Your master plumber or HVACR license from the Board of Plumbing, Heating, Ventilation, Air Conditioning and Refrigeration Examiners is not the same as your Division of Revenue business license. You need both. Operating without a business license is illegal and carries a fine of up to $3,000 or up to two years in prison.

Common Mistake 2: Not Maintaining Your License or Forgetting Renewal

Your license expires on October 31 of even-numbered years and requires biennial renewal with continuing education. If you let it lapse, you cannot work in the trade legally. Mark your calendar now, plan your CE hours in advance, and budget for the renewal fee and any late fees if you miss the deadline.

Common Mistake 3: Working Under Someone Else's License

Some contractors try to operate without a master on staff by borrowing an established master's license. This is not legal. The supervising master must be the worker's employer or be employed full time by the same business entity, and allowing another person to use your license is grounds for discipline.

Timeline and Expected Results

Here is the typical order of steps for starting a plumbing or HVAC business in Delaware:

• Gather credentials (journeyman certificate or documentation of seven years supervised work) and EPA CFC certification if pursuing HVACR
• Submit master license application with $173 fee
• Board reviews application; you may be asked for clarification
• Board schedules your exam; you receive notification of date and location
• You take the master exam
• Board notifies you of results; if you pass, your license is issued
• In parallel: Form your business entity if you want an LLC or corporation, file a trade name (DBA) if needed, and apply for your state business license and contractor license through Delaware One Stop

The Board does not publish a standard timeline, so budget extra time if the Board requests additional documentation or if you need to retake the exam.

Once you are licensed, you can legally take plumbing and HVAC jobs in Delaware. Your business will be subject to the state gross receipts tax, local plumbing and HVAC codes (which vary by municipality), and ongoing continuing education requirements every two years.

Disclaimer

This article is informational only and does not constitute legal or tax advice. Delaware plumbing and HVAC licensing laws are found in Delaware Code Title 24, Chapter 18, and are administered by the Board of Plumbing, Heating, Ventilation, Air Conditioning and Refrigeration Examiners. Laws and fees are subject to change. Before starting your business, consult with a Delaware-licensed attorney regarding business formation and liability, and with a Delaware CPA or accountant regarding tax obligations and gross receipts tax filing. For the most current fee schedules, continuing education requirements, and application procedures, visit dpr.delaware.gov/boards/plumbers/ and revenue.delaware.gov.