Washington State's New Plumbing Contractor Rules Take Effect July 2025: What You Need to Know

New Mandatory Structure for Plumbing Work in Washington

Starting July 1, 2025, Washington State will enforce a revised plumbing contractor licensing framework that affects how plumbing services are delivered and who can perform them. The state's Department of Labor & Industries finalized these rules in 2021 and is now implementing them across the state.

The core change is straightforward: all plumbing work must be performed by licensed plumbing contractors. This means that general contractors—even those with broad construction credentials—can no longer perform plumbing work themselves. Instead, they must subcontract it to a licensed plumbing contractor. Similarly, only licensed plumbing contractors can hire and supervise certified plumbers.

What Licensed Plumbing Contractors Must Have

To operate as a licensed plumbing contractor in Washington, your business will need to meet several requirements:

• A valid business license
• General liability insurance
• A $6,000 bond or assigned savings account
• A designated full-time certified plumber on staff who serves as your Designated Plumber

The Designated Plumber is not a ceremonial position; it signals that your firm has a full-time, qualified professional responsible for the work your company produces. This reflects a shift toward accountability and professional responsibility in the plumbing trade.

Licensing and Transition Costs

The two-year plumbing contractor license costs $139.10, with an additional $50 fee to formally file your Designated Plumber designation. While these fees are modest, the bond or savings account requirement represents a material commitment and may affect cash flow for smaller operations.

A transition window exists for existing registered contractors. If you already hold a construction contractor registration and perform plumbing work, submitting an application by September 1, 2025 will keep you in compliance during the changeover period. After that date, the state will stop issuing or renewing specialty registrations for plumbing contractors under the old framework.

What This Means for Your Business

If you operate a plumbing business, expect to finalize your Designated Plumber designation and ensure your insurance and bond are in place well before July 1. Delayed compliance could disrupt your ability to take on work.

If you run a general contracting or home-service business (HVAC, appliance repair, or mixed trades) and currently perform plumbing work, you have two paths forward:

1. Partner with a licensed plumbing contractor: Establish relationships with licensed subcontractors to handle plumbing-related jobs. This may increase your project costs but ensures compliance.
2. Obtain both licenses: You can hold both a plumbing contractor license and general contractor registration, allowing you to perform both plumbing and non-plumbing work. This requires the added Designated Plumber overhead but preserves operational flexibility.

For firms that choose to subcontract, the timeline becomes critical. Building a reliable network of licensed plumbing partners now—before July 1—will prevent job delays and customer service failures once the rules take effect.

Broader Implications

These changes reflect a broader industry trend toward credentialing and accountability in skilled trades. States increasingly require proof of expertise, financial stability, and management oversight before allowing contractors to operate. While compliance carries costs, the upside is reduced competition from unlicensed operators and clearer customer trust in licensed work.

The designation requirement also creates a management challenge: your full-time Designated Plumber becomes a business asset and a potential constraint on growth. If that person leaves or becomes unavailable, you'll need a transition plan to maintain licensing status.

Review your current operations, insurance, and staffing model against these requirements now. A three- to four-month runway should be sufficient to apply, secure bonding, and notify customers of any process changes—but waiting until June 2025 could leave you scrambling.