Plumbing is one of the most tightly regulated trades for good reason. A plumbing error can cause water damage, structural rot, mold, contaminated drinking water, and gas leaks — damage that is expensive, sometimes dangerous, and often invisible until it’s severe. Licensing and insurance exist to protect you from exactly those scenarios. Knowing what to ask — and how to verify the answers — is the most important thing you can do before a plumber touches a single pipe in your home.
“In my years doing post-incident inspections, the jobs that went wrong had one thing in common almost every time: the homeowner never verified the plumber’s licence. A number on a website or a logo on a van means nothing. Two minutes with the relevant trade licensing body database tells you whether that plumber is actually licensed, whether their licence is current, and whether any complaints have been filed. That two minutes is the best investment a homeowner can make.”
— Dana Reyes, licensed master plumber and plumbing inspector with 21 years of experience in residential and commercial plumbing in many regions
Table of Contents
Licensing Questions
Are you licensed as a plumber in this region?
In many regions, plumbers must be licensed through the relevant trade licensing body. Other regions have equivalent bodies — the Technical Safety BC in some regions, the some regions Apprenticeship and Trade Certification Commission, and so on. In the US, licensing requirements vary by state and sometimes by municipality.
Ask directly for the plumber’s licence number and the issuing body. Then verify it yourself.
What a good answer looks like: A specific licence number offered without hesitation, the name of the licensing body, and the class of licence (journeyperson or master).
Are you a journeyperson or master plumber?
These are two different licence classes with different scopes of authority.
A journeyperson plumber has completed their apprenticeship and is qualified to perform most residential plumbing work independently. However, in many jurisdictions, certain jobs — particularly those involving new connections to the main water supply or drain stack, or work that requires a plumbing permit — must be performed or directly supervised by a master plumber.
A master plumber holds an advanced licence that allows them to take on the full scope of plumbing work, pull permits in their own name, and supervise journeyperson plumbers and apprentices.
Ask which licence class your job requires, and confirm the person doing the work holds the right one.
What a good answer looks like: A clear explanation of their licence class and a confirmation that it’s appropriate for your specific job.
Is your licence currently in good standing?
A licence that has lapsed, been suspended, or had conditions placed on it is not a valid licence for your purposes. Don’t just ask whether they’re licensed — ask whether the licence is currently active and in good standing. Then verify it in the licensing database yourself.
What a good answer looks like: Confirmed active status with no conditions or suspensions — verifiable through the regional or state licensing body.
Do your apprentices or helpers hold their own credentials?
On many plumbing jobs, a licensed plumber brings along apprentices or helpers who do much of the hands-on work. Apprentices working toward their licence must be supervised by a licensed journeyperson or master plumber. Ask specifically: who will be on the job, what their credentials are, and how much direct supervision the licensed plumber will provide.
What a good answer looks like: Named crew members with their credential status disclosed, and a clear description of how the licensed plumber supervises the work.
Insurance Questions
Do you carry general liability insurance?
General liability insurance covers property damage the plumber causes during the job — a cracked tile, a flooded basement from a misconnected fitting, damage to a neighboring unit in a condo. Ask for a certificate of insurance, not just verbal confirmation. Verify the policy is current and the coverage limits are adequate.
For residential plumbing work, a minimum of $1–2 million in liability coverage is a reasonable baseline.
What a good answer looks like: A certificate of insurance provided within 24 hours, showing current coverage and adequate limits.
Do you carry workers’ compensation coverage for your workers?
In many regions, most employers in the construction and trade sector are required to carry Workplace Safety and Insurance Board (workers’ compensation coverage) coverage for their workers. If a worker is injured on your property and the plumber doesn’t have workers’ compensation coverage, you could face liability for that worker’s medical costs and lost income.
Don’t accept a verbal assurance. Request a workers’ compensation coverage Clearance Certificate — you can verify it directly at your workers’ compensation board’s website using the plumber’s account number. In other regions and US states, equivalent workers’ compensation verification is available through the relevant authority.
What a good answer looks like: A workers’ compensation coverage Clearance Certificate showing the plumber’s account is in good standing, obtained directly from workers’ compensation coverage.
Does your insurance cover subcontractors?
If the plumber brings in helpers or subcontractors, ask whether they’re covered under the plumber’s liability policy or carry their own. An uninsured helper doing work in your home is a gap in coverage that could cost you.
What a good answer looks like: Written confirmation — either that helpers are covered under the plumber’s policy, or separate certificates for each worker on the job.
How to Verify What You’ve Been Told
Licence verification:
– your region: the relevant trade licensing body (collegeoftrades.Ca)
– some regions: Technical Safety BC (technicalsafetybc.Ca)
– some regions: some regions Apprenticeship and Industry Training
– US: Check your state’s licensing board — most have online lookup tools
Search by the plumber’s name or company name, and confirm both the licence class and current status.
Insurance verification:
Call the insurer listed on the certificate of insurance and confirm the policy is active, the coverage amounts match what you were told, and the policy won’t expire before your job is complete.
Workers’ compensation coverage verification:
Go to your regional workers’ compensation board’s website and use its clearance/verification tool,” and enter the plumber’s business name or workers’ compensation coverage account number. The clearance certificate will confirm whether their account is in good standing.
Why This Matters More Than You Think
An unlicensed plumber who does a poor job on a pipe connection may leave you with a slow leak inside a wall that causes mold for months before you notice. If they’re not licensed, you have no regulatory body to complain to and no guarantee the work meets code. If they’re not insured, any damage they cause comes out of your pocket.
A licensed, insured plumber isn’t just a credential — it’s accountability. They’re held to a standard, they can be reported if they fall short of it, and their insurance backs up their work if something goes wrong.
Related Questions
- Questions to Ask a Plumber Before You Hire One
- Questions to Ask a Plumber About Permits and Inspections
- Red Flags When Hiring a Plumber
- What to Do If a Plumber Does Bad Work
Have a question we didn’t cover? Submit it below.