How to Find a Good Plumber in London

What makes a plumber good, in the way that matters to you

A good plumber correctly identifies what has failed, is qualified to work on it, and tells you the cost structure before they start rather than after. That is the whole of it. Arriving quickly and being pleasant are nice, but neither stops you paying twice for the same fault because the first visit guessed.

This matters more in London because the work is not one trade. Someone can be an excellent plumber and still be unable to lawfully touch an unvented hot water cylinder, because stored hot water is a separate competence. Someone can be Gas Safe registered and not signed off for the appliance type in your flat. Someone can be superb on copper and useless at tracing a leak under a liquid screed floor, because that needs different equipment. So the question is never is this a good plumber. It is whether this is the right person for this fault, and how you would know.

We run 20 engineers and they are not interchangeable. Any firm with a real spread of skills should tell you which of its people is coming and what that person does. A firm that will not is either very small and pretending otherwise, or not routing jobs on skill at all.

The five minute checks that filter out most of the bad options

Do these before you speak to anyone. They take about five minutes, cost nothing, and remove most of the ways this goes wrong. None of them require you to know anything about plumbing.

Start with registration, because it has a definite answer. Gas work requires Gas Safe registration, and the register is public and searchable by business name, postcode or registration number. Look the firm up yourself rather than trusting a logo on a website, because the logo is an image file and the register is the record. The ID card an engineer carries lists on the back the specific categories they are signed off for, and you are entitled to look at it. If your hot water comes from a white pressurised cylinder with a cluster of valves and a small open funnel in the pipe above it, ask by name whether the attending engineer holds the unvented hot water qualification. Our page on how to check a plumber on the Gas Safe Register walks through the search itself and explains what the categories on the back of the card mean.

Then check the business exists as a business: a company number you can look up, a real address, and public liability insurance the firm will confirm the value of. None of that proves competence. It proves there is something to come back to if the work goes wrong. Then read reviews sideways rather than downwards. The star average aggregates people rating politeness. What is useful is detail, and the replies to the bad ones. A firm that answers a complaint with specifics keeps records of jobs. A firm that answers with an accusation is showing you how a dispute with you would go.

• Search the Gas Safe register yourself for the business or the engineer.
• Ask by name about the unvented qualification if you have a pressurised cylinder.
• Look up the company number and check the business is real and current.
• Ask for confirmation of public liability insurance and the figure it covers.
• Read the detailed reviews and the replies to bad ones, not the star average.

Why the sponsored results and top map listings are not the best plumbers

The businesses in the block marked sponsored, and the map listings carrying an ad label, are there because they paid to be there. It is an auction, not a quality ranking, and emergency plumbing is one of the most expensive categories to bid in because a person with water coming through a ceiling clicks the first thing they see.

The consequence is arithmetic rather than morality. A business paying per click recovers that cost from the jobs it wins, and since only a fraction of clicks book, each completed job carries the cost of all the clicks that did not. That comes out of the price, or out of the time spent on your job, or out of what gets recommended once someone is standing in your kitchen. Nobody is doing anything wrong by advertising. The incentive is simply pointed away from you.

The second consequence is who you actually reach. A large share of the most aggressive paid listings are lead brokers rather than plumbers. You ring what looks like a local firm, the call is sold to whichever contractor is buying leads in your postcode that day, and the person who turns up has paid for your phone call and needs the visit to pay. So scroll. Organic listings and unlabelled map businesses are ranked on relevance and proximity rather than spend, which is a weak signal of competence but a better one than a bid.

• An ad label or a sponsored block means a bid, not a ranking.
• A company name that is a keyword rather than a name, claiming every borough at once, is usually a lead operation.
• A map pin at an address with no premises behind it is worth noticing.
• Ask directly: are you the company attending, or do you pass the job on.

There is nothing wrong with a plumber advertising. What is worth avoiding is treating the money spent to reach you first as evidence of anything about the work. It is evidence of a marketing budget.

How call-out fees work, and why a free call-out is rarely free

A call-out fee pays for a qualified person to travel to you with a stocked van and spend a defined period diagnosing and usually fixing the fault. It exists because attendance costs money whether or not work follows, and a firm that charges it openly does not need the visit to turn into a sale.

The two honest structures are a fixed fee covering attendance plus a stated period of labour, or an hourly rate with the first hour stated up front. Both are fine. What you need before anyone travels is which of the two applies, what it covers, what happens when the time runs out, how parts are charged, and whether evenings and weekends differ.

Free call-out is worth a second of thought. The visit still costs the business, so it is recovered somewhere: a higher hourly rate once work begins, a markup on parts, a minimum charge appearing after diagnosis, or a strong incentive to find work that justifies the trip. That last one is the expensive version, because it never appears on the invoice as a line you can question. Get the structure in writing, by text or email, before the van moves. Not a total, which nobody can give honestly for a fault they have not seen, but the structure. Our own rate sits on the pricing page and is quoted before we attend.

• Fixed attendance fee or hourly rate, and what the first period includes.
• What the charge becomes once the included time is used up.
• Whether parts are at cost, at a markup, or inside a fixed price.
• Whether evenings, weekends and bank holidays carry a different rate.
• Whether the diagnosis fee is deducted if the repair goes ahead.

What to ask on the phone, and what a good answer sounds like

The phone call carries most of the information and takes about three minutes. You are listening for two things: whether the person understands your system, and whether they are comfortable being specific about money and about their own limits.

Ask what they think it might be. A good answer names two or three possibilities, says which they would check first and why, then says plainly that they cannot be certain until they see it. A bad answer is either total certainty about a fault nobody has looked at, which usually precedes a fixed sales pitch on arrival, or a flat refusal to speculate, which often means there is no engineer on the call.

Ask who is attending and what they are qualified for. A good answer gives a first name, says what that person mainly works on, and volunteers the relevant qualification unprompted. A bad answer is an engineer described only as available, with a vague assurance that all of them are fully qualified for everything.

Then listen to how price is handled. Being asked for the make and model, the postcode and the symptom before a figure is offered is a good sign, because the figure then relates to something. A single low number offered immediately with no questions is a booking tactic, and that number tends to grow once someone is inside.

• What do you think it could be, and what would you check first.
• Who is attending, and what do they mainly work on.
• Are you the firm attending, or is the job passed on.
• What is the charging structure, and what does the first period cover.
• What happens if a part is needed that is not on the van.
• What will I be given in writing when the work is done.

The pressure patterns that cost people the most money

The most expensive thing that happens to householders is not a bad repair. It is a repair that was never needed, sold under time pressure to someone already stressed because water was going somewhere it should not.

The first pattern is the jump from symptom to replacement. You called about no hot water and within ten minutes the conversation is a new boiler. Sometimes that is right, because a cylinder full of scale or a boiler with a cracked heat exchanger is not worth repairing. But the sequence is diagnosis, then a named failed component, then repair compared against replacement with reasons. If nobody has named a part, nobody has diagnosed anything.

The second is urgency applied to something that is not urgent. Uncontrolled water, a gas smell, scalding water at a tap and a discharge pipe running from an unvented cylinder are genuine emergencies. A cylinder five years past its expected life does not need a decision today, and someone telling you it does, while holding a card machine in your hallway, is managing you rather than advising you.

The third is the upsell attached to the real job. While the panel is off, would you like a flush, a filter, a scale reducer. Some of those are genuinely worth having in hard water, which most of the London supply is. The test is whether the person can explain what problem it solves on your system and what happens if you decline. If the answer is a warning rather than an explanation, decline and think about it later.

If you feel rushed, you are allowed to stop. Ask for the diagnosis in writing, pay for the attendance, and take a day. A repair that is genuinely necessary today will still be necessary tomorrow, and anything actually dangerous should have been made safe before money was discussed.

Match the plumber to the building

Victorian and Edwardian conversions carry pipework altered and buried by four generations of trades, much of it in voids nobody has opened since. A leak there is a detection problem before it is a repair problem, so ask what they use to find it before anything gets cut. Purpose built blocks often have thermal stores such as Pulsacoil units, or heat interface units fed from a communal system: not ordinary cylinders, model specific parts, and a wrong diagnosis usually means replacing a unit that needed a component. Say the model name on the phone and listen for whether it registers. New builds normally have underfloor heating under liquid screed, which cannot be chased across without wrecking the floor, and may still sit inside a developer warranty that an outside trade can affect.

Across nearly all of it the water is hard. Scale sits behind a large share of hot water faults here: immersion elements failing, plate heat exchangers blocking, cylinders losing capacity, shower cartridges seizing. A plumber who understands the local supply treats a scaled component as a symptom of an ongoing condition and tells you what to do about the cause, rather than fitting the same part again. On a sealed system that distinction is the whole of an unvented cylinder repair, because the component that failed and the water that killed it are two separate conversations.

What you should be holding when the job is finished

You should end up with a written record naming what was wrong, what was done and what it cost, itemised rather than totalled. That document is what makes a warranty claim, an insurance claim or a follow up visit possible, and it is the thing most often missing when something goes wrong later.

Gas work comes with its own safety documentation. An unvented cylinder service should produce a record of the checks and readings, because that is what a manufacturer asks for if the unit fails inside warranty and what a letting agent or buyer asks for later. Keep it with the appliance manuals. The next engineer will read it, and a documented history shortens the second diagnosis.

• The named component that failed and why.
• Parts listed separately from labour.
• The rate or fixed fee applied, and any out of hours variation.
• Business name, address and the engineer name or registration number.
• Gas safety documentation where gas work was carried out.
• Service records with readings for an unvented cylinder.

Find one before you need one

The best time to choose a plumber is a quiet Tuesday when nothing is wrong, because every part of this gets harder with water on the floor. Get one small job done by a firm you have checked: a tap washer, a service, a stopcock that has seized. You learn more from one uneventful visit than from any amount of research, and you end up with a number in your phone and an engineer who has already seen your system. Note where your stopcock and consumer unit are while you are at it, because those two facts prevent more damage than anything else on this page.