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Division of
Professional Regulation

Master Plumber Licensure

General Information

A Master Plumber can design, install, construct, replace, service, repair, alter, or modify the pipes, fixtures, and other apparatus used for bringing the water supply into a building and removing liquid and water-carried wastes from a building.  A Master Plumber can also install and connect gas piping.

You need a Master HVACR or Master HVACR Restricted license in addition to a Master Plumber license if you design, install, construct, maintain, service, repair, alter, or modify a product or equipment including gas piping in heating and air conditioning, refrigeration, ventilation, or process cooling or heating systems. See Master HVACR and Master HVACR Restricted Licensure for more information.

Information on How to Apply for a License in DELPROS

All applications are submitted our online system DELPROS. We no longer accept paper applications.


In order to apply for a license or submit a service request, you must first have a DELPROS user account. To LOG IN or CREATE a DELPROS (Delaware Professional Regulation Online Services) user account:

  1. Go to:
  2. Click GO on the Apply/Manage a License and Service Requests tile.
  3. If you do not have a DELPROS user account, click the REGISTER button on the left side of page for NEW USERS.
  4. If you already have a DELPROS user account, enter your email address and password on the right side for EXISTING USERS and click the LOGIN button.

DELPROS allows you to save your incomplete application and return to it later to finish the process. You only have six (6) months to submit your application once you begin.

  • If you do not submit your application within six months of starting it, you will be required to restart the entire online application again.

You may check the status of your application online throughout the entire application process by using the “View Application Status” feature in DELPROS on your e-License dashboard.


  1. Know the requirements for the license you are pursuing.
  2. Request and gather all documents required to upload on the Attachments page. All information and forms are located on your profession’s webpages.


On the ATTACHMENTS page of your application, you may be instructed to:

  • either “attach” or “upload” the required document(s) directly to your application. This means you will find the document(s) saved on your computer or device and upload it to your application.
  • click “acknowledge.” This means you will either have to mail the documents yourself or request the “third-party” mail the document(s) directly to the Board office.
    • Examples of “third-party forms” are transcripts from schools, employment verifications from a supervisor, and license verifications from another state.
  • Forms requiring a supervisor signature, seal, or notary may have to be MAILED to the Board office directly UNLESS the document specifically indicates to UPLOAD the document.

The requirements for this license type are provided in the following section(s).

Requirements for All Applicants

These requirements apply to both reciprocity and examination applications. In addition to submitting the application and fee in DELPROS, you must submit:

  • State/Jurisdiction Licensure Verification sent directly to the Board office from each state or jurisdiction in which you currently hold or have ever held a license.
    • The jurisdiction may be a state, U.S. territory, District of Columbia or any other governmental jurisdiction such as a city or county. In the state of Pennsylvania, Plumbing licenses are not issued by a state board. If the only current license you hold was issued by a Pennsylvania municipality or other jurisdiction, you must apply by examination.
    • If a license was for a plumbing business that covered all its employees, instead of your own license as an individual, it is not necessary to obtain a license verification for that business.
  • To prove your work experience for periods of employment (when required under Exam and Reciprocity sections below), arrange for your supervisor(s) to complete the Verification of Employment form.
    • If you cannot obtain the required Verification of Employment form from the supervisor, you may substitute tax form W-2 or an affidavit of the employer or officer of the employing company. You must also enclose a statement explaining why you cannot obtain the Verification of Employment form from the supervisor.
    • To prove your work experience for periods of self-employment, you may submit tax form Schedule C.
    • Acceptance of proof of experience is at the Board’s discretion.

Examination Applicants

The following requirements apply to applications by examination in addition to the requirements in the previous section above. The documents that you must submit is determined by whether or not you have a “Journeyman Certificate”. A “Journeyman Certificate” is issued by a federally-approved plumbing apprenticeship program such as the Delaware Department of Labor.

  • If you have a journeyman certificate, you must submit:
    • Copy of your apprenticeship program Certificate of Completion.
    • Proof of at least two years work experience under the supervision of a master licensee after receiving Certificate.
  • If you do not have a journeyman certificate, you must submit:
    • Proof of at least seven years work experience under supervision of a master licensee.
    • The Board will review your experience and if approved, you will be notified that you may take the Apprenticeship By-Pass Exam, offered by Delaware apprenticeship schools. After you receive approval notification, you may call one of the following schools to schedule your test date:
      • Castle County – New Castle County VoTech (302) 683-3643
      • Kent County – PolyTech H.S. (302) 697-4545
      • Sussex County – Sussex Tech, Georgetown (302) 856-9035
  • Arrange for the Board to receive the exam results after you pass the exam with at least 70%.

When the Board approves you to sit for the Master exam, the Board office will send you a candidate information packet. For more information about the Master exam, see Examinations.

Reciprocity Applicants

The following requirements apply to applications by reciprocity in addition to the requirements in the Requirements for All Applicants section above.

If none of the jurisdictions where you hold a current license has licensure standards that are “substantially similar” to those of Delaware, proof of experience is required. The table below shows whether to submit proof of experience.


IF you hold a current Plumber license in any of these states… THEN the licensure standards… AND you…
Connecticut, Iowa, Maryland are substantially similar do not need to submit any proof of experience.
Alabama, Arkansas, District of Columbia, Florida, Georgia, Michigan, New Hampshire, New Jersey, North Carolina, Ohio, Rhode Island, South Carolina, Virginia, West Virginia are not substantially similar must submit proof of practicing a minimum of seven (7) years after receiving licensure as a Master in the reciprocating jurisdiction.
any state or U.S. territory not listed above must be evaluated by the Board must submit a copy of the other jurisdiction’s law and regulations for evaluation.


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