Before Your Plumber Arrives

Why a bit of prep saves a lot of money

A plumber charges by the hour from the moment they pull up outside. Spending twenty minutes the night before clearing the under-sink cupboard, locating your stopcock and taking a couple of photos of the drip can shave a full hour off the invoice — and sometimes solves the problem so quickly that a more expensive call-out is avoided entirely.

This checklist is the one we send to readers who message us at 11pm in a panic because water is coming through the ceiling. It assumes you do not know where your isolation valves are, and walks you through everything you can usefully do between booking the plumber and their van turning up.

The 24-hour checklist

Run through these the day before the plumber is due. None of them require any skill beyond what a normal householder already has — but they collectively shave real money off the final invoice.

• Find and test your main stopcock. Nine times out of ten it is under the kitchen sink, but it can also be in a downstairs loo, a hallway cupboard or — in older houses — under the floor by the front door. Turn it clockwise until it stops, then turn a cold tap on to confirm the flow drops to a dribble. If it will not turn, do not force it; warn the plumber so they can bring a replacement stopcock.
• Turn off the water heating. If the leak is near a hot pipe or the problem is with the boiler, switch the heating and hot water to OFF at the programmer and, for older gravity systems, shut the valve on the cold-water tank in the loft. This stops the cylinder boiling dry while the mains are off.
• Clear access to the problem. Empty the cupboard, move the washing machine out a foot, lift the bath panel if you can — anywhere the plumber will need to reach. Put towels down on carpet and a plastic sheet on wooden floors. Access time is billable time.
• Take photos and a short video. Film the leak, drip or pressure gauge for 20 seconds. Note whether it is worse when a tap is running, when the boiler fires, or only overnight. This is especially useful if the fault is intermittent and might not be happening when the plumber arrives.
• Gather the paperwork. Find your boiler's service record, the instruction manual if you have it, and the original installation certificate. For unvented cylinders, dig out the G3 benchmark. For underfloor heating, locate the manifold schematic. A plumber who knows the model saves guesswork.
• Note the meter reading before they start. Read your water meter (if you have one) and jot down the number and time. If a major leak is suspected you will have an objective before-and-after figure for the water company.
• Write down what you have already tried. Did you bleed the radiator? Turn the boiler off and on? Reset the pressure? A plumber who knows what has been ruled out will skip straight to the cause.
• Put pets in another room. Sounds obvious but it is the single most common reason plumbers lose 15 minutes — a dog guarding the airing cupboard where the cylinder lives.

Tools worth having ready

These are the things the plumber will either ask for, borrow, or charge you labour to go fetch. Keeping a small dedicated set in a cupboard means you never lose the 20 minutes that turn into the next half-hour block on the invoice. All prices move, so we link to live Amazon UK searches rather than fixed ASINs.

Questions to ask when they arrive

Asked politely on the doorstep, these five or six questions filter out 90% of the problems that turn into complaints later. A professional will welcome them; a cowboy will get irritated.

• Can you confirm your Gas Safe ID before touching the boiler? For any gas work, ask for the card and verify the number at GasSafeRegister.co.uk on your phone while they set up.
• What is the cause, in plain English? A good plumber should be able to say 'the rubber washer has perished' or 'the flux joint has failed', not just 'it is leaking'. If they cannot explain the cause, they will struggle to prevent it happening again.
• Is it worth replacing the part or the whole unit? For cisterns, old taps and 15-year-old combi boilers this matters. An honest plumber will tell you when a repair is a false economy.
• How long is the workmanship guarantee? Get the length in writing on the receipt — 12 months labour is standard.
• Will you leave the old parts here? So you can check they have been replaced and see the actual failure mode.
• Should I book a follow-up service? For boilers and unvented cylinders, an annual service keeps warranty valid. The plumber can usually pencil one in for 12 months out before they leave.

Red flags during the visit

If you see any of these on the day, slow things down. You are not obliged to let anyone continue work you are uncomfortable with — even if they've already been there an hour.

• They refuse to show a Gas Safe card for gas work. Non-negotiable — send them away. A real Gas Safe engineer carries their card and is used to being asked.
• They quote a fixed price without looking at the job first. Plumbers who quote over the phone before seeing the fault are either padding the price to cover unknowns or will add 'extras' once on site. Get the price after the look-at, not before.
• They turn off the water but cannot show you where the stopcock is. Means they are working blind. If anything goes wrong they will not be able to stop it quickly.
• They want cash only, no receipt. Beyond the obvious tax issue, with no receipt you have no comeback under Consumer Rights Act 2015 for faulty workmanship.

What to do after the visit

The paperwork and follow-up is where homeowners most often lose money — warranties unregistered, certificates not received, insurance claims unfiled. Run through this list before you pay the final invoice.

• Ask for a receipt itemising labour, parts and VAT — needed if you ever claim on home insurance.
• Register any new boiler or cylinder with the manufacturer within 30 days — this activates the parts warranty (often 7-10 years on Worcester Bosch, Viessmann, Vaillant).
• Photograph the Gas Safe engineer's Building Regulations compliance certificate before they leave. It arrives by post later but you want proof in the meantime.
• For unvented cylinders, make sure you have the G3 benchmark completed in the manual.
• Read the water meter one more time — any unexpected movement over the next 24 hours suggests a leak has not fully been found.

Find a plumber in Kent

• Plumbers in Kent — county-level directory
• Plumbers in Maidstone
• Plumbers in Canterbury
• Plumbers in Dartford
• Plumbers in Tunbridge Wells
• Plumbers in Ashford

Related guides

• How to Choose a Plumber — the sister guide to this one, covering qualifications, quoting and insurance.
• Trade Shop — curated tools and homeowner kit, by category.
• All Guides — every NearbyTraders homeowner guide, in one place.