Plumbing Licensing Requirements

In 2020, the Legislature passed significant changes to plumbing laws (SB 6170). This page highlights a few of the changes, including the creation of a new plumbing contractor license. Plumbing and related industries worked together to propose the changes to address certified plumber shortages, expand plumber training opportunities, and increase consumer protection.

How to apply

To register with L&I as a licensed plumbing contractor, you must:

  • Complete the plumbing contractor application (F627-051-000) for regular plumbing contractors or the combination contractor application (F500-104-000) for Pump Industry contractors.
  • Obtain a Surety Bond (F627-047-000) or Assigned Savings Account (F627-049-000) $6,000.
  • Obtain a Certificate of Liability Insurance.
  • Complete and notarize application.
  • Pay the required application fees.
  • Assign (F627-052-000) your designated plumber who carries a plumber certification with L&I.
    • To remove the designated plumber, the plumber will need to un-assign (F627-053-000) from the Plumbing Contractor.

Phase 2 rules are being finalized to implement the changes to Chapter 18.106 RCW, which took effect July 1, 2021. Learn more about the rules. Additional phase 3 rule making will begin soon focused on some outstanding items and the phase out of the construction contractor plumbing specialty.

Check back often for updates, or stay informed about the new requirements by signing up for our email distribution list below. Review the new licensing requirements FAQs.

Plumbing Contractors

Plumbing Contractors

Beginning July 1, 2021, the “specialty plumbing” registration was no longer valid, and general contractors could no longer perform work with a certified plumber. All plumbing contract work must be performed by a new Licensed Plumbing Contractor under Chapter 18.106 RCW.

  • Licensed plumbing contractors can choose to also be registered as general contractors under Chapter 18.27 RCW, to perform non-plumbing works such as installing cabinets, tile, etc.
  • Plumbing contractors must designate to L&I, a certified plumber as the “dedicated plumber” for their company. This could be an owner/partner or a full-time employee.
General Contractors

General Contractors

As of July 1, 2021, general contractors cannot offer, advertise, and/or bid on projects that require plumbing work. 

  • General contractors can choose to also be licensed as plumbing contractors under Chapter 18.106 RCW to perform contract plumbing work.

Residential Service Plumbers

Residential Service Plumbers

Residential Service Plumber is a new category in the plumbing program. These plumbers can perform service work on an existing “single family dwelling and/or duplex.”