What to ask a plumber before they start

The right questions take five minutes and save you hundreds. Here they are, and here’s what a decent answer sounds like.

Plumbing jobs go sideways for the same reasons every time – nobody agreed a price, nobody agreed a scope, and nobody checked if the person doing gas work was actually allowed to. There are plumbers listed across the WotsItCalled directory, from sole traders to proper outfits, and the good ones won’t mind any of these questions. The dodgy ones will.

Sort the job before you sort the plumber

Before you ring anyone, work out what you’re actually dealing with. The words you use on the phone change who’s right for the job.

• Dripping tap, blocked sink, leaky radiator valve – bread and butter. Any general plumber can handle this. You’re looking for someone local who’ll turn up without charging a fortune for the trip.
• Anything involving gas or a boiler – Gas Safe territory. Not optional, not negotiable. If they’re not on the Gas Safe register, they shouldn’t be touching it.
• New bathroom, kitchen sink plumbing, full pipe replacement – this is project work. You want quotes in writing, a timeline, and ideally photos of jobs they’ve done before.
• Burst pipe at midnight – that’s emergency call-out. Price comes second. You just need someone who answers the phone and can get there fast.

Asking a bathroom fitter to come out at 11pm for a leak is how you end up paying twice. Match the job to the right kind of plumber.

Five questions to ask before they start

The phone call tells you most of what you need to know. Ask these five and pay attention to how they answer – the tone matters as much as the words.

1. Are you Gas Safe registered, and what’s your number? If the job touches gas, this is the only answer that matters. A genuine plumber will give you the number without hesitating. Cross-check it at gassaferegister.co.uk – takes about ten seconds.
2. Can I get a written quote before any work starts? Verbal prices on the phone aren’t worth much. A proper plumber will come and look, then put the price in writing. If they’re dodging a site visit for anything bigger than a washer change, that’s a flag.
3. Is that a fixed price or an estimate? There’s a massive difference. Fixed means that’s what you’ll pay unless the job changes. Estimate means it could go up – and it usually does. Make sure you know which one you’re agreeing to.
4. How’s the call-out charged? Some charge a flat call-out fee. Some fold it into the hourly rate. Some waive it if you go ahead with the work. All fair, as long as they tell you up front. If you find out at the end, something’s off.
5. When can you get here and how long will it take? You’re not interrogating them, you’re planning your week. A decent plumber gives you a real answer. Vague ones who can’t commit to a window are usually juggling too much.

Bonus one for bigger jobs: ask who’s doing the actual work. Some outfits quote for the job then send a different person on the day. Fine if they’re good. Not fine if you weren’t told.

Red flags that should end the conversation

A few things that mean you should ring the next one on your list:

• Cash only, no receipt. Everyone takes cash. A proper plumber still gives you a receipt. If they’re insisting on cash and nothing in writing, walk away.
• Vans with no business name, no insurance details. Not a dealbreaker for a sole trader, but combined with anything else on this list it’s a pattern.
• Wildly low quote compared to the others. Sometimes that’s an honest guy keeping overheads down. More often it’s someone planning to bump the price halfway through with “unexpected issues”.
• Pressure to start today. Unless it’s an actual emergency, urgency is a sales tactic. Decent plumbers are usually booked a few days out anyway.

Where to find one near you

The plumbers directory on WotsItCalled is free to browse and covers every major UK city. If you’re after someone local, the city-scoped pages are the quickest way in: plumbers in Liverpool, Manchester, Birmingham, Wirral, and the rest. No signup, no account – just listings, phone numbers, and reviews.

After the job: what a decent plumber leaves behind

A good plumber tidies up on the way out. Not a frantic deep clean, but the basics: old parts bagged and labelled, drip trays emptied, cut-offs swept up, a quick wipe of the work area. If you’ve got a new boiler or new valves, they should walk you through how it works – where the isolation valve is, how to top up the pressure, what the warning lights mean.

• A written invoice. Itemised, with their business details, VAT number if applicable, and a date.
• Warranty details. Most plumbers guarantee their labour for 12 months. Boilers carry the manufacturer’s warranty on top – usually 5-10 years if registered properly.
• Registration paperwork. For a new boiler, Gas Safe notifies Building Control automatically. You should get a certificate in the post within a fortnight.
• Benchmark logbook entry. New boilers come with a Benchmark commissioning checklist. Make sure it’s filled in and signed – it’s a condition of the manufacturer’s warranty.

The short version

• Match the job to the type of plumber before you ring round – emergency, gas, or project work are three different shortlists.
• Gas Safe registration is a legal requirement for gas and boiler work. Check the number on the register.
• Ask for a written quote. Fixed price beats estimate every time.
• Confirm the call-out charge up front so there are no surprises on the bill.
• Vague timings, cash-only, or pressure to start today – all signs to ring the next one.

WotsItCalled is a free UK business directory. No signup, no catch. Find the place everyone’s on about, or browse the full plumbers directory.