Your faucet leaks. You open Google Maps. Twenty-two plumbers show up in a 3 km radius, all with 4.8 stars and five reviews. Which one is worth your $800? And which one turns a $150 leak into a $3,500 job site?
Here are the six questions we ask plumbers before letting them in, the four red flags that should make you hang up, and what an honest quote looks like in Montreal in 2026.
Question 1 — "Are you a CMMTQ member?"
The Corporation des Maîtres Mécaniciens en Tuyauterie du Québec is the professional body for master plumbers in Quebec. A member has demonstrated technical competence, carries sufficient liability insurance, and their work is covered by the Qualité Habitation warranty plan.
Verify the status on the CMMTQ website (cmmtq.org) — type the company name. If it doesn't come up, keep looking.
Question 2 — "What's your RBQ licence number?"
The Régie du bâtiment du Québec issues contractor licences. For residential plumbing, you want subcategory 15.9.2 (plumbing work), active and not suspended.
Verify on rbq.gouv.qc.ca. A good plumber gives you the number without hesitation — and a commercial plumber adds the appropriate subcategories for project scale, as detailed in our article commercial plumbing in Montreal.
Question 3 — "Can you provide a detailed written quote?"
For any intervention over an hour or $300, a written quote is standard. It should contain:
- Line-by-line description of the work — not "miscellaneous" or "as needed".
- Materials list with brands and specs.
- Labour vs. materials breakdown.
- Taxes (GST and QST) separately.
- Quote validity (30 days typically).
- Payment terms — deposit, progress, final balance.
A plumber who refuses to put numbers on paper doesn't want to be held to those numbers. That's red flag #1.
Question 4 — "What's your workmanship warranty?"
The industry standard in Montreal is 12 months of workmanship warranty, plus manufacturer warranty on parts (often 2 to 10 years). Quality shops sometimes offer 2 or 5 years — a good sign of confidence in their own work.
Get the warranty in writing. "Yeah, guaranteed" over the phone is worth nothing six months later when a new problem appears.
Question 5 — "Can I see three recent references?"
A plumber active in Montreal for more than five years has hundreds of satisfied clients. Three recent references (under 6 months, similar in nature to your project) take ten minutes to provide.
What you ask the references:
- Was the final price close to the quote? (More than 15% over without a valid reason is a red flag.)
- Were deadlines respected?
- Was the job site clean each evening?
- Did a problem show up later? If so, how was it handled?
Question 6 — "Are you insured?"
Minimum $2 million civil liability for residential, $5 million for commercial. Get the insurance certificate with the company name and expiry date. A plumber who causes major water damage without insurance leaves you filing a claim with your own insurer — and the coverage loss that can follow.
The 4 red flags
- Door-to-door canvassing — "We were in the area, your drain looks like trouble." A serious plumber doesn't cold-knock doors.
- Cash-only payment, no invoice. That's under-the-table work, zero warranty, zero recourse if it goes sideways.
- Vague pricing like "We'll see on site" for a simple intervention. For a genuine emergency, fine — for a faucet install, no.
- No paperwork — no contract, no invoice, no receipt for materials. Run.
What a good quote looks like
Here's an example for a 50-gallon electric water heater replacement:
- Giant 50 gal water heater, 4500W, 12-yr manufacturer warranty: $720
- ½" ball shut-off valve (replaced): $28
- Fittings, solder, protection device: $45
- Labour (2 hrs): $220
- Old tank disposal: $40
- Subtotal: $1,053 — GST + QST: $157.58 — Total: $1,210.58
- Workmanship warranty: 12 months from installation
Precise numbers, brands named, warranty in writing. That's what gets signed.
Three myths to drop
"The cheapest is a scam." Not necessarily. A solo plumber with low overhead can be genuinely competitive. What matters is the detailed quote and the 6 questions.
"The most expensive is always the best." No. Some large companies mark up for their corporate overhead, not for their quality.
"A handy friend is just as good." Legally, an unlicensed person cannot work on your pressurized plumbing. If it's found out, your insurance is voided for any later water damage — even unrelated.
When the price varies between two quotes, why?
Honest gaps come from three sources:
- Material quality — an IKEA vanity vs. a custom one is $2,000 of justifiable difference.
- Scope — one replaces just the faucet, the other also replaces corroded shut-off valves. Both are right, but one prevents a future leak.
- Warranty — 2 years vs. 12 months. That's measurable value.
Ask for the explanation of the gap. A good plumber gives it willingly.
Summary — the 6 questions and 4 red flags
- CMMTQ? — verifiable online
- RBQ 15.9.2? — verifiable online
- Detailed written quote? — always
- Workmanship warranty? — 12 months minimum
- 3 recent references? — ten minutes to provide
- Insurance? — certificate on file
- Red flags: canvassing, cash-only, vague pricing, no paperwork
Plomberie PSF checks every box. CMMTQ, RBQ, written quote every time, 12- to 24-month workmanship warranty depending on scope, references on request, insurance up to date. Over ten years in Montreal, zero shortcuts. For an honest quote: (514) 655-6560 or /contact. And if you already have another plumber's quote you want a second opinion on, we review it free.