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Please note that false information provided at the time of permit application or failure to adhere to the following requirements may result in the permit being revoked and a stop work order being issued.

Laws and regulations governing contractors and plumbers

  • Contractor registration rules are found in RCW 18.27
  • Plumber certification rules are found in RCW 18.106

For inquiries regarding these regulations, please contact the Washington State Department of Labor and Industries.

Who may purchase a plumbing permit and perform the work authorized by the permit

  • Property owner
    When a property owner ("owner") purchases a permit, the owner is the contractor and shall be so noted on the permit. The owner may acquire the services of a registered contractor, provided that the contractor meets all of the state rules and regulations pertaining to contractor registration and plumber certification. Such contractor may perform the work authorized by the owner's permit. The property owner is allowed to enlist the help of a friend, relative, neighbor or other acquaintance, provided that those assisting are not receiving any form of compensation to perform the work.

  • Building contractor
    When a building contractor purchases a permit, that person is the contractor and shall be so noted on the permit. Verification of current contractor registration is required. The building contractor may acquire the services of a registered plumbing contractor, provided that the plumbing contractor meets all of the state rules and regulations pertaining to contractor registration and plumber certification. Such contractor may perform the work authorized by the owners permit. The building contractor may also utilize employees when said employee(s) meet all of the state rules and regulations pertaining to plumber certification.

  • Plumbing contractor
    When a plumbing contractor purchases a permit, that person is the contractor and shall be so noted on the permit. Verification of current contractor registration is required. Employees of the plumbing contractor who perform the plumbing installation shall meet all of the state rules and regulations pertaining to plumber certification.

Actions that may be taken if a person fails to meet the above requirements

Failure to meet the minimum requirements of contractor registration or plumber certification rules and regulations may be referred to the Washington State Department of Labor and Industries for investigation and possible enforcement. Where information provided to this department is falsified, or where the above requirements are not met, a stop work order may be issued. In addition, the chief plumbing inspector has the authority to revoke the permit.

Contractor registration requirements

RCW 18.27.020
Registration required—Prohibited acts—Criminal penalty—Monitoring program.

  1. Every contractor shall register with the department.

  2. It is a gross misdemeanor for any contractor to:
    1. Advertise, offer to do work, submit a bid, or perform any work as a contractor without being registered as required by this chapter;
    2. Advertise, offer to do work, submit a bid, or perform any work as a contractor when the contractor's registration is suspended or revoked;
    3. Use a false or expired registration number in purchasing or offering to purchase an advertisement for which a contractor registration number is required;
    4. Transfer a valid registration to an unregistered contractor or allow an unregistered contractor to work under a registration issued to another contractor; or
    5. Subcontract to or use an unregistered contractor.

  3. It is not unlawful for a registered contractor to employ an unregistered contractor who was registered at the time he or she entered into a contract with the registered contractor, unless the registered contractor or his or her representative has been notified in writing by the department of labor and industries that the contractor has become unregistered.

  4. All gross misdemeanor actions under this chapter shall be prosecuted in the county where the infraction occurs.

  5. A person is guilty of a separate gross misdemeanor for each day worked if, after the person receives a citation from the department, the person works while unregistered, or while his or her registration is suspended or revoked, or works under a registration issued to another contractor. A person is guilty of a separate gross misdemeanor for each worksite on which he or she violates subsection (2) of this section. Nothing in this subsection applies to a registered contractor.

  6. The director by rule shall establish a two-year audit and monitoring program for a contractor not registered under this chapter who becomes registered after receiving an infraction or conviction under this chapter as an unregistered contractor. The director shall notify the departments of revenue and employment security of the infractions or convictions and shall cooperate with these departments to determine whether any taxes or registration, license, or other fees or penalties are owed the state.

Who can install plumbing without being a certified plumber

RCW 18.106.150
Exemptions.

  1. Nothing in this chapter shall be construed to require that a person obtain a license or a certified plumber in order to do plumbing work at his or her residence or farm or place of business or on other property owned by him or her.

  2. A current certificate of competency or apprentice permit is not required for:
    1. Persons performing plumbing work on a farm; or
    2. Certified journey level electricians, certified residential specialty electricians, or electrical trainees working for an electrical contractor and performing exempt work under RCW 18.27.090(18).

  3. Nothing in this chapter shall be intended to derogate from or dispense with the requirements of any valid plumbing code enacted by a political subdivision of the state, except that no code shall require the holder of a certificate of competency to demonstrate any additional proof of competency or obtain any other license or pay any fee in order to engage in the trade of plumbing.

  4. This chapter shall not apply to common carriers subject to Part I of the Interstate Commerce Act, nor to their officers and employees.

  5. Nothing in this chapter shall be construed to apply to any farm, business, industrial plant, or corporation doing plumbing work on premises it owns or operates.

  6. Nothing in this chapter shall be construed to restrict the right of any householder to assist or receive assistance from a friend, neighbor, relative, or other person when none of the individuals doing such plumbing hold themselves out as engaged in the trade or business of plumbing.