None of these questions are rude, and a good plumber will answer all seven without flinching. If someone gets cagey about any of them, that reaction is itself your answer. Here is the checklist, in the order we would run it if we were hiring a tradie for our own house.
The pre-hire checklist
| Question | Why it matters | A good answer sounds like |
|---|---|---|
| What is your QBCC licence number? | Plumbing is licensed work in QLD; you can verify online in 2 minutes | A number you can check, given without hesitation (ours is 15243081) |
| Are you insured? | Public liability protects your property if something goes wrong | Yes, current, and happy to show the certificate |
| Is the quote fixed or an estimate? | Estimates grow; fixed prices do not | A fixed price in writing before work starts |
| What warranty do you offer on labour? | Separates workmanship cover from manufacturer cover | A stated period, in writing, on the invoice |
| Who is actually doing the work? | Some outfits quote with a veteran and send an apprentice | The person quoting is the person on the tools |
| What paperwork will I get? | Compliance certificates matter for insurance and resale | Certificate or Form 4 where required, plus a proper invoice |
| Can I see recent reviews? | Pattern of reviews beats a slick website | A public profile you can read yourself |
How do I check a plumber's licence in Queensland?
Ask for the licence number, then verify it yourself on the QBCC's free online licence search before anyone starts work. The search shows whether the licence is current, what classes it covers, and any conditions. Every legitimate plumber expects this question and most of us print the number on our quotes, invoices and vans. One wording note that matters: a QBCC licence covers plumbing and drainage work. Gas work is licensed separately under Queensland's gas safety framework, so if your job involves gas, ask specifically whether the person holds a gas work licence as well. A tradie who explains that distinction clearly, rather than waving one number at everything, is showing you they understand their own compliance obligations.
Should I insist on a fixed price?
For most residential jobs, yes. A fixed price means the risk of the job running long sits with the plumber, not with you, and it forces the quoting plumber to actually look at the job properly before committing. We quote fixed prices on almost everything, from a $250 to $400 machine drain clear to full hot water changeovers, and where a job genuinely cannot be priced sight unseen, such as work hidden under a slab, we say so and quote after inspection rather than inventing a number. The question to ask is simple: "Is this the final figure, and what would change it?" A trustworthy answer lists the specific conditions that would trigger a revised quote, in writing, before the extra work happens.
What paperwork should a Queensland plumber give me?
At minimum, a written quote before the job and a detailed invoice after it, showing the licence number. For notifiable and regulated work, Queensland requires compliance documentation, including a Form 4 for relevant new installations, and gas work must come with a compliance certificate. Keep all of it. This paperwork is what your insurer asks for after a water damage claim, what a buyer's solicitor asks for at sale time, and what Gold Coast City Council requires if you ever claim a concealed leak remission. A plumber who shrugs at the paperwork question is telling you the compliance side of their work is an afterthought, and that is exactly the part that protects you.
What are the red flags that should end the conversation?
Cash-only pricing with no invoice, a quote that is dramatically cheaper than every other quote, pressure to sign today, no licence number on the paperwork, and vague answers about who is turning up. The pattern we see across the rectification jobs we attend is depressingly consistent: the original work was cheap, undocumented, and done by someone the homeowner never vetted. Paying a licensed, insured, reviewed plumber a fair fixed price is cheaper than paying twice.
Ready to put us through the checklist?
Go for it. QBCC licence 15243081, insured, owner-operator so the person who quotes is the person on the tools, fixed prices in writing, warranty on the invoice, and 27 Google reviews at 5.0 stars you can read for yourself.
Sources: QBCC online licence search; Plumbing and Drainage Act 2018 (Qld); Queensland gas work licensing framework under the Petroleum and Gas legislation.
Vetting plumbers for a big job? Call Hills Plumbing & Gas on 0472 657 042 or start with our Bathroom Renovations service page and ask us all seven questions. We enjoy this part.