Why Checking a Plumber’s License in Ontario Isn’t Just a Good Idea — It’s Essential
You’ve got a burst pipe. A leaky water heater. Or maybe your basement is flooding. You need a plumber — now. But in the rush to fix the problem, it’s easy to grab the first name you find on Google or a Facebook ad.
Here’s the hard truth: Not every plumber in Ontario is licensed. And hiring an unlicensed one could cost you thousands in repairs, void your home insurance, or even put your family’s safety at risk.
That’s why knowing how to check if a plumber is licensed in Ontario isn’t just a smart move — it’s non-negotiable. In this guide, we’ll walk you through exactly how to do it, step by step, using official tools and trusted resources. No guesswork. No scams. Just peace of mind.
Step 1: Understand Who Regulates Plumbers in Ontario
In Ontario, plumbers aren’t regulated by just any agency — they’re overseen by the Ontario College of Trades (OCOT), which was replaced in 2023 by the Skilled Trades Ontario (STO). This government body ensures all tradespeople — including plumbers — meet strict competency standards.
“Only licensed plumbers are legally allowed to install, repair, or modify plumbing systems that connect to municipal water or sewer lines.”
— Skilled Trades Ontario Official Guidelines
There are two main types of licensed plumbers in Ontario:
| Journeyperson Plumber | Valid Certificate of Qualification (C of Q) | Install, repair, maintain plumbing systems in homes and businesses |
| Master Plumber | Master Plumber License | Can supervise journeypersons, pull permits, and run a plumbing business |
⚠️ Warning: Anyone claiming to be a “plumber” without a valid STO license is operating illegally. And if something goes wrong? You’re on the hook for damages.
Step 2: Use the Official STO License Verification Tool (Free & Instant)
The fastest, most reliable way to check if a plumber is licensed in Ontario is through the official Skilled Trades Ontario public registry.
Here’s how:
- Go to: https://www.sto.on.ca/public-register (official government link)
- In the search bar, type the plumber’s full legal name (e.g., “John Smith”).
- Optionally, add their company name or city to narrow results.
- Click Search.
✅ If licensed, you’ll see:
- Their full name
- License number
- Trade classification (e.g., “Plumber”)
- License status: Active, Expired, or Suspended
- Issue and expiry dates
❌ If no results appear, they are not licensed — do not hire them.
💡 Pro Tip: Always search using the exact spelling of their name. Even a typo can lead to false negatives.
Real-Life Case: In 2024, a Toronto homeowner hired an unlicensed “plumber” who installed a gas line improperly. A gas leak caused a small fire. Insurance denied the claim because the worker wasn’t licensed. The homeowner paid $18,000 out of pocket. — Source: Ontario Fire Marshal Report
Step 3: Ask for Proof — And Verify It Yourself
Even if a plumber shows you a card or says, “I’m licensed,” never take their word for it. Scammers print fake IDs. Always:
- Ask to see their original Certificate of Qualification (C of Q) or Master Plumber license.
- Check the license number on the STO website yourself.
- Confirm the name on the card matches the name on the invoice.
🚫 Red Flags:
- “I’m licensed, but my card is at home.”
- “I work under my boss’s license.”
- “I don’t need a license for small jobs.”
Myth Busted: There’s no such thing as a “small job” exemption in Ontario. Any work involving water, gas, or sewer lines requires a licensed professional — period.
Why You Should Never Hire an Unlicensed Plumber
Let’s break down the risks — clearly and honestly.
| Insurance Denial | Most home insurance policies require work to be done by licensed tradespeople. Unlicensed work = denied claims. |
| Safety Hazards | Improper gas or water installations can cause leaks, mold, explosions, or contaminated drinking water. |
| No Legal Recourse | If they do poor work, you can’t file a complaint with a regulatory body. No recourse. |
| Fines & Replacements | Municipalities can force you to tear out unlicensed work and redo it — at your cost. |
| No Warranty | Licensed plumbers offer warranties. Unlicensed? “Sorry, I’m gone.” |
According to the Canadian Home Builders’ Association, over 30% of plumbing-related insurance claims in Ontario in 2023 involved unlicensed contractors.
Bonus: How to Find a Licensed Plumber in Ontario (Without the Scams)
Want to go beyond just checking? Here’s how to find a reputable, licensed plumber:
- Use the STO Public Register — Search by city or postal code.
- Check Google Reviews — Look for 4.5+ stars with real photos and detailed reviews.
- Ask for References — A licensed pro will gladly provide past client contacts.
- Verify Business Registration — Use the Ontario Business Registry to confirm they’re a registered business.
- Avoid Door-to-Door Offers — Most cold-call or door-knocking “plumbers” are unlicensed. Legit companies don’t operate that way.
💬 “I used to hire guys off Craigslist until my water heater exploded. Now I only use plumbers I verify on STO. It’s saved me $12,000 and a lot of stress.”
— Maria T., Hamilton, ON
FAQ: Your Top Questions About Licensed Plumbers in Ontario, Answered
Q1: Can a handyman do plumbing work in Ontario?
No. A handyman can do minor tasks like replacing a faucet washer or unclogging a sink — but any work involving pipes connected to municipal water or sewer systems requires a licensed plumber. If they’re installing a new water heater, rerouting pipes, or connecting to gas lines — they must be licensed.
Q2: How long does a plumber’s license last in Ontario?
A Journeyperson Plumber’s Certificate of Qualification is valid for life — but their STO registration must be renewed annually. Always check the status and expiry date on the STO public register. A license that says “Active” but expired in 2023? That’s not valid.
Q3: What if I hire an unlicensed plumber and something goes wrong?
You’re financially and legally responsible. Municipalities can issue fines to homeowners for unpermitted work. Your home insurance likely won’t cover damages. And if someone gets hurt (e.g., from a gas leak), you could face civil liability. Always verify first.
Q4: Do I need a permit for plumbing work in Ontario?
Yes — almost always. Most plumbing projects (new fixtures, water heater replacement, sewer line work) require a building permit from your local municipality. Only licensed plumbers can pull these permits. If your plumber says, “I’ll skip the permit,” that’s a huge red flag.
Q5: How much does it cost to get a plumbing license in Ontario?
Becoming a licensed plumber takes years: 4–5 years of apprenticeship, 8,000+ hours of on-the-job training, and passing a provincial exam. The exam fee alone is around $300–$500. That’s why licensed plumbers charge more — but you’re paying for skill, safety, and accountability.
Q6: Can I check a plumber’s license by phone?
Yes. Call Skilled Trades Ontario at 1-833-666-7827 (toll-free) during business hours (8:30 AM – 4:30 PM ET). Have the plumber’s full name ready. But for speed and convenience, always use the online registry — it’s instant.
Conclusion: Don’t Risk Your Home — Verify First
Knowing how to check if a plumber is licensed in Ontario isn’t just about avoiding fraud — it’s about protecting your family, your home, and your wallet. One quick 2-minute check on the Skilled Trades Ontario website can save you thousands in repairs, insurance denials, or even disaster.
✅ Remember:
- Always verify via STO Public Register
- Never trust verbal promises — check the license number yourself
- If it feels too good to be true (e.g., “$99 drain cleaning”), it probably is
Share this guide with friends, family, or neighbors who might be searching for a plumber. One share could prevent a household crisis.
👉 Got a story about hiring a licensed plumber? Or a scary experience with an unlicensed one? Drop it in the comments below — your experience could save someone else.
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