Colorado Plumber License Reciprocity: Out-of-State Endorsement Guide

If you're a licensed plumber in another state and planning to move to Colorado, the first thing to understand is that Colorado does not maintain blanket reciprocal agreements with any state. Your existing license doesn't transfer automatically, and there's no "just show up and start working" pathway. Instead, DORA uses a case-by-case endorsement process that evaluates whether your home state's licensing standards are substantially equivalent to Colorado's.

How Endorsement Works

The endorsement method is Colorado's mechanism for crediting out-of-state experience and exams without requiring you to start from scratch. Here's the process:

Step 1: Verify your current license is active. You must hold an active plumbing license in your origin state, and you must have held it for a minimum of six months before applying for endorsement in Colorado. A recently issued or currently suspended license doesn't qualify.

Step 2: Request state-to-state verification. DORA requires direct verification from your origin state's licensing agency confirming that you successfully passed a comparable state plumbing exam. "Comparable" means the exam was based on the current or previous edition of the plumbing code adopted by the Colorado State Plumbing Board — in practice, the International Plumbing Code (IPC).

If your state uses the Uniform Plumbing Code (UPC) or a state-specific exam instead of the IPC, DORA evaluates equivalency on a case-by-case basis. If they determine the exam isn't comparable, you'll need to sit for the Colorado PSI exam to obtain licensure.

Step 3: Submit employer-verified experience. Out-of-state experience hours must be documented with the same rigor as in-state hours. Your former employers — who must be registered or licensed plumbing contractors in their state — need to provide experience verification on letterhead or through DORA's experience forms. A photocopy of your out-of-state license is required as part of the application, but it does not substitute for employer affidavits.

Step 4: Submit your DORA application. File through the MyLicense Office portal with your passing score verification (from either your origin state exam or the Colorado PSI exam if required), notarized experience affidavits, a copy of your active out-of-state license, and the applicable application fee ($100 residential, $120 journeyworker, $140 master).

When You'll Need to Take the Colorado Exam

DORA doesn't automatically waive the exam for every endorsement applicant. You'll need to sit for the Colorado PSI exam if:

• Your origin state doesn't test on the IPC or uses a non-equivalent exam
• Your origin state's licensing agency can't verify exam passage (some states don't retain old records)
• DORA determines your exam and experience don't meet Colorado's "substantially equivalent" standard

The exam itself covers the International Plumbing Code, International Fuel Gas Code, and State Plumbing Board Rules. Passing scores are 70% for residential and journeyworker tiers, 75% for master. Schedule through PSI four to six weeks in advance, and bring a valid government-issued photo ID.

The Self-Verification Trap

One of the most frustrating aspects of the endorsement process: even if you've been running your own plumbing business in another state for a decade, you cannot verify your own experience hours. Board Rule 1.4 A(3)(f) prohibits self-verification regardless of how long you've been licensed or how established your business is.

For out-of-state applicants who are sole proprietors or business owners, this means you cannot sign your own verification. A co-owner or office manager on company letterhead may verify the hours when the original supervisor is unavailable; if neither applies, confirm the acceptable path with DORA. Tax records, W-2s, and business filings can support your application but don't replace the affidavit requirement.

States That Do and Don't Align

DORA doesn't publish a list of states with "pre-approved" equivalency, because every application is reviewed individually. However, some general patterns hold:

• IPC-adopting states tend to have smoother endorsement evaluations, since Colorado's exam is IPC-based
• UPC states (common on the West Coast and in some Midwest states) face a higher likelihood of needing the Colorado exam
• States without statewide plumbing licensing (where licensing is done at the city or county level) present more complex evaluations, since DORA needs to assess whether the local exam and standards are comparable to a state-level program

The safest assumption if you're relocating: prepare for the possibility that you'll need to take the Colorado PSI exam, even if your home state has rigorous licensing standards. Having a backup plan saves you weeks of uncertainty.

Timeline Expectations

The endorsement process isn't instant. Between gathering employer affidavits from out-of-state (especially from companies you worked for years ago), requesting state-to-state license verification, and DORA's processing time, expect the full endorsement application to take several weeks to a few months.

If your application is submitted without all required documentation, DORA holds the incomplete file for up to one year before requiring you to restart. Getting everything assembled before you submit saves you from this clock.

What You Can't Do While Waiting

Until your Colorado license is issued, do not assume that your out-of-state license authorizes plumbing work in Colorado. If you need to start working immediately, the supervised path is to register as an apprentice with a Colorado plumbing contractor while your endorsement application processes. Confirm with DORA how any resulting apprentice hours would be treated if the endorsement ultimately requires additional documentation.

The Colorado Plumber License Guide includes an Endorsement Document Tracker designed for out-of-state applicants — it maps every required document, the agencies you need to contact, and the sequence that keeps the process moving without gaps.

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