What is the biggest red flag when hiring a plumber?

Refusing to put the charging structure in writing before attending. You are not asking for a total, which nobody can give honestly for an unseen fault. You are asking whether attendance is fixed or hourly, what the first period covers, what the rate becomes afterwards, and how parts are charged. Any firm that prices honestly can text that in a minute. One that insists on explaining it only once an engineer is inside is protecting its freedom to decide the number later.

Is it a bad sign if a plumber will not give a price over the phone?

It depends what you asked for. Refusing to total an unseen job is correct and honest, because the total depends on what has failed. Refusing to describe the charging structure is a different thing and is a warning sign. The good version sounds like this: attendance covers a stated period of labour, here is what happens after that, parts are charged this way, and I cannot tell you the total until I have seen it.

How can I tell if a plumbing company is actually a lead generator?

Ask whether they are the company attending or whether the job is passed on, and ask for the first name and speciality of the engineer coming. A lead operation cannot answer either. Supporting signs are a company name that is a keyword rather than a name, a national non geographic phone number, a map pin at an address with no visible premises, coverage claimed across all of Greater London plus other cities, and a call handler who cannot answer any technical question.

Should I avoid plumbers who advertise at the top of Google?

Not automatically, but do not read the position as a recommendation. Sponsored results and ad labelled map listings are bought at auction, so they tell you about a marketing budget rather than about the engineer. A business paying per click recovers that cost from the jobs it wins, and only a fraction of clicks become bookings. Scroll to the organic listings, then apply the same phone call test to whoever you find there.

Is a plumber who diagnoses my fault over the phone a bad sign?

A confident, single, certain diagnosis is a bad sign. A good engineer names two or three possibilities, says which they would check first and why, then says plainly they cannot be certain until they look. Total certainty about an unexamined fault, especially when it lands on the most expensive cause, means the conclusion came before the evidence. A flat refusal to discuss it at all usually means nobody technical is on the call.

What should I do if a plumber pressures me to decide immediately?

Stop and take a day. Genuine emergencies are uncontrolled water, a smell of gas, scalding water at a tap or a discharge pipe running constantly from an unvented cylinder, and those should be made safe before money is discussed at all. Anything else can wait overnight. Ask for the diagnosis in writing naming the component that has failed, pay for the attendance you agreed, and get a second opinion before committing to a replacement.

Do bad reviews mean I should avoid a plumber?

Read the replies rather than counting the stars. A firm that answers a complaint with specifics, dates and what it did next keeps proper job records, which is exactly what you want when something goes wrong. A firm that answers with an accusation against the customer is showing you how a dispute with you would go. A perfect average made of short, generic entries tells you less than three detailed reviews describing an actual fault.

Is a cheap quote a warning sign?

A low figure offered instantly, before anyone has asked what system you have or what the symptom is, is a booking tactic rather than a quote. It relates to nothing, and it usually grows once the job has been opened up. Being asked for the make, the model, the postcode and the symptom before any number appears is the better sign, because then the figure is attached to something real that can be checked later.

What paperwork should I insist on before hiring someone?

Before the visit, the charging structure by text or email. After the work, an itemised invoice naming the component that failed, parts listed separately from labour, the rate or fixed fee applied, and the business and engineer details. Gas work carries its own safety documentation, and an unvented cylinder service should produce a record of the checks and readings. Without that record a warranty claim, an insurance claim or a second opinion becomes much harder.

Signs of a Bad Plumber, Before You Hire One

The signs of a bad plumber are all visible before anyone gets in a van: vagueness about money, refusal to put anything in writing, certainty about a fault nobody has looked at, and an inability to say who is attending or what that person is qualified for. You do not need to know anything about plumbing to catch them. You need to listen to a three minute phone call, ask for one thing by text, and notice what the answers avoid.

What are the warning signs before any work starts?

Six things predict a bad job more reliably than anything on a website: no clear charging structure before attendance, nothing offered in writing, a diagnosis delivered with certainty over the phone, no name or speciality for the engineer attending, urgency applied to a fault nobody has examined, and no answer to the simple question of whether they are the company attending or are passing the job on. Any one of those is worth a second question. Two or three together and you should ring someone else.

What they have in common is that each removes a record or a limit. A price with no structure cannot be disputed later. A diagnosis with no named component cannot be checked. An unnamed engineer cannot be looked up. A firm that keeps all three loose has room to move on the day, and that room is not there for your benefit.

The signs people rely on instead are weaker. A tidy website costs a few hundred pounds, a star average mostly measures politeness, and a top position is a budget. None of them touch whether the person attending can identify what has failed.

No charging structure given before the van moves.
Nothing they will confirm by text or email.
A confident diagnosis of a fault they have not seen.
No name and no speciality for the attending engineer.
Urgency applied before anyone has examined anything.
No straight answer on whether the job is passed to a third party.

How a bad plumber answers the phone

A firm with engineers behind it asks you questions. A firm that only wants the booking asks for your postcode and your card details. That difference is audible inside the first minute, and the call is the most informative three minutes of the whole process.

Listen for whether anyone asks what you have. A competent handler or engineer wants to know what the hot water comes from, how old it is, what the symptom is and whether anything changed just before. If your water is stored, they want to know whether it is a vented tank fed from a loft cistern, a pressurised unvented cylinder with a small open funnel in the pipe above it, or a thermal store in a purpose built block. Those need different parts and in some cases a different qualification. Skipping all of that means your job is routed on availability alone.

The opposite sign is the call that is entirely about closing: a figure offered before any question, a push to take a slot in the next hour, card details wanted to hold an appointment. Test it by asking what they think it could be. Deflection or a flat refusal usually means there is no engineer anywhere near the conversation.

Notice too whether they will tell you no. A firm that says it does not hold the unvented ticket and will not touch a pressurised cylinder has told you something useful. Somebody who says yes to every system and every fault is not listening. An unvented cylinder repair is the clearest example of that, because the work is notifiable and the ticket behind it is either held by the person attending or it is not, and no amount of confidence on the phone changes which.

They ask what system you have before quoting anything.
They ask what changed just before the fault appeared.
They can say what they do not do, and who it needs instead.
They do not need card details to book a visit.

What they will not put in writing

Ask for the charging structure by text or email before anyone travels. That one request separates firms faster than any other test, because a business that intends to be straight with you already has that paragraph saved somewhere and will send it in a minute. A business that wants its options open will suddenly prefer to explain it when the engineer arrives. It belongs on the short list of questions to ask a plumber before anyone travels, alongside who is attending and what that person is signed off for.

You are not asking for a total. Nobody can honestly total a fault they have not seen. You are asking for the structure: fixed attendance fee or hourly rate, what labour the first charge includes, what the rate becomes after that, how parts are charged, whether evenings and weekends differ, and whether a diagnosis charge comes off the bill if the repair goes ahead. Six lines. Anyone who prices honestly can send them.

The dodge to listen for is a range so wide it carries no information, followed by it depends what we find. Of course it does. That is why you asked about the structure and not the total. When the structure itself is called unknowable, what is being protected is the freedom to decide the number once you are committed and the water is off.

The same test applies at the other end. Ask what paperwork you get. It should be an itemised invoice naming the failed component, parts listed separately from labour, and the rate applied. We will sort you out on the day means no record of what was wrong, which makes any later claim harder.

Our own rate lives on the pricing page and is confirmed before we attend. The principle matters more than whose rate it is: get the structure in writing before the van moves, from anyone you hire.

How they describe the diagnosis tells you most of it

The most reliable single signal is how someone talks about a fault they have not yet seen. A good engineer gives you two or three candidates, says which they would check first and why, then says plainly that they cannot be sure until they look. That is not hedging. That is what honest diagnosis sounds like from someone who has not been in the room.

A bad one goes one of two ways. Either total certainty, usually landing on the most expensive possible cause, which means a conclusion was reached before any evidence existed and the visit is a formality. Or total refusal to engage, which usually means nobody technical is on the call and the job is going to whoever picks it up.

The tell is whether components get named. Real diagnosis is specific: an immersion element scaled and failed, a motorised valve whose actuator is not driving over, a plate heat exchanger blocked so the heating works and the hot water does not, a pump running but not moving water, a cylinder coil furred up. Someone who can name what they would test and what rules it in or out has done this before. When the language stays at your system is old, nothing has been diagnosed and you are being softened up for a replacement quote.

This continues after they arrive. Ask what has failed and why it cannot be repaired. You want a part, a reason, and repair weighed against replacement. Replacement is sometimes right, but that conclusion comes after a named component, not instead of one.

Nobody can tell you who is attending

Ask for the first name of the engineer coming and what they mainly work on. A firm that routes jobs on skill answers in a sentence. A firm that cannot answer at all is either much smaller than it appears, or is not the firm attending.

That second case matters more than people realise. A lot of the heaviest advertising in this trade is placed by lead generators rather than plumbers. You ring what looks like a local company, the call is sold to whichever contractor is buying work in your postcode that day, and the engineer who turns up has effectively paid for your phone call. Nobody in that chain is doing anything unlawful. The problem is structural: the handler cannot answer technical questions because he is not a plumber, and the person attending has a cost to recover before the job starts.

We run 20 engineers and they are not interchangeable. The one servicing unvented cylinders all week is not the one to send to a thermal store, and neither is the one you want tracing a leak under a screed floor. Any firm with a real spread of skills can say who is coming and why.

Ask: are you the company attending, or is this passed on.
Ask for the first name of the engineer and their speciality.
Check the address is a real premises, not a mail box.
Be wary of a firm claiming every borough and several cities.

Free call-out, and other prices that are not prices

A free call-out is not a warning sign by itself, but it deserves one more question, because the visit costs the business money whether or not work follows and that money comes back somewhere. Usually it is a higher rate once work begins, a markup on parts, a minimum charge appearing after diagnosis, or an incentive to find work that justifies the trip. The last is the expensive version, because it never appears on the invoice as a line you can argue with. An attendance fee stated openly does the opposite: the firm is paid for the visit either way, so it has no reason to invent work.

The other price that is not a price is the very low figure offered instantly, with no questions about your system. It is a booking tactic, it relates to nothing, and it tends to grow once the job is opened up.

Treat the top of the search results the same way. Sponsored blocks and ad labelled map entries are bought at auction rather than ranked on quality, and a business paying per click recovers that cost from the jobs it wins. That is arithmetic, not an accusation. The position tells you about a marketing budget and nothing about the engineer.

Scroll past the ad labelled block. Organic and unlabelled map listings are ranked on relevance and proximity rather than spend, which is a weak signal of competence but a better one than a bid.

Urgency applied before anyone has looked

Manufactured urgency costs householders more than bad workmanship does, and it is usually visible before the work is agreed. Genuine emergencies exist: uncontrolled water, a smell of gas, scalding water at a tap, a discharge pipe running constantly from an unvented cylinder. A cylinder past its expected life is not one of them, and anyone saying it needs deciding in the next twenty minutes, while holding a card machine in your hallway, is managing you rather than advising you.

The phone version is the slot that will be gone in ten minutes, usually paired with a deposit request. The on site version is the jump from symptom straight to replacement with no named failed part in between. You rang about no hot water and within ten minutes the conversation is a new cylinder. The order matters: diagnosis, named component, then repair weighed against replacement with reasons.

The third version is the upsell bolted onto the real job. While the panel is off, would you like a flush, a filter, a scale reducer. Some are worth having in London, where the supply is hard and scale sits behind a lot of hot water faults. The test is whether the person can explain what it solves on your system. An explanation is advice. A warning with no mechanism behind it is a sale.

You are allowed to stop. Ask for the diagnosis in writing, pay for the attendance, and take a day. Anything genuinely dangerous should have been made safe before money was ever discussed.

The signs that show up in the first ten minutes on site

Some signals only appear once someone is in the property, and you can still act on them, because the expensive commitment usually comes later. The first is whether they look before they talk. A competent engineer finds the stopcock, checks what the controls are doing and reads any existing service record before offering a conclusion. Someone who walks in with the answer already decided did not get it from your system.

The second is identification. For gas work, ask to see the ID card and read the back of it, which lists the categories that person is signed off for. Registration alone does not mean signed off for your appliance type. Nobody competent minds being asked, and irritation at the question is itself the answer. Knowing how to check a plumber on the Gas Safe Register before anyone arrives makes it a shorter conversation, because you already know what the entry should say and what it will not tell you.

The third is what they do with an unexpected part. Vans do not carry everything. The honest response is to make the system safe, name the part, and say how the return visit is charged. The one to be wary of is an expensive component swapped on a guess with the reasoning kept vague.

The fourth is how they treat the building. Victorian and Edwardian conversions have pipework buried by four generations of trades, so a leak there is a detection problem before it is a repair problem, and anyone reaching for a chisel before locating it precisely will make your job larger. New builds usually have underfloor heating in liquid screed. If nobody asks what is under the floor before cutting into it, stop the job.

What to do when you spot one

Before work starts, the answer is simple: do not book, or unbook. You owe nothing for a phone call. Have a second number ready so the choice is not between this firm and nobody, because that pressure is what pushes people into the bad option.

If someone is already in the property and something feels wrong, you can still stop. Ask for the diagnosis in writing, pay for the attendance you agreed, and decline the rest. Photograph the appliance and anything opened up before they leave, and pay by a method with protection behind it rather than a bank transfer.

The best defence is built when nothing is wrong. Find a firm on a quiet weekday and give it a small job: a service, a seized stopcock, a dripping tap. You learn more from one uneventful visit than from any amount of review reading, and you end up with a number in your phone and an engineer who has seen your system. That is what how to find a good plumber comes down to in practice: doing the checking on a day when nothing is broken, so the decision is already made when something is. With water on the floor, people click the first result and skip every check on this page.

Questions we get asked

What is the biggest red flag when hiring a plumber?: Refusing to put the charging structure in writing before attending. You are not asking for a total, which nobody can give honestly for an unseen fault. You are asking whether attendance is fixed or hourly, what the first period covers, what the rate becomes afterwards, and how parts are charged. Any firm that prices honestly can text that in a minute. One that insists on explaining it only once an engineer is inside is protecting its freedom to decide the number later.
Is it a bad sign if a plumber will not give a price over the phone?: It depends what you asked for. Refusing to total an unseen job is correct and honest, because the total depends on what has failed. Refusing to describe the charging structure is a different thing and is a warning sign. The good version sounds like this: attendance covers a stated period of labour, here is what happens after that, parts are charged this way, and I cannot tell you the total until I have seen it.
How can I tell if a plumbing company is actually a lead generator?: Ask whether they are the company attending or whether the job is passed on, and ask for the first name and speciality of the engineer coming. A lead operation cannot answer either. Supporting signs are a company name that is a keyword rather than a name, a national non geographic phone number, a map pin at an address with no visible premises, coverage claimed across all of Greater London plus other cities, and a call handler who cannot answer any technical question.
Should I avoid plumbers who advertise at the top of Google?: Not automatically, but do not read the position as a recommendation. Sponsored results and ad labelled map listings are bought at auction, so they tell you about a marketing budget rather than about the engineer. A business paying per click recovers that cost from the jobs it wins, and only a fraction of clicks become bookings. Scroll to the organic listings, then apply the same phone call test to whoever you find there.
Is a plumber who diagnoses my fault over the phone a bad sign?: A confident, single, certain diagnosis is a bad sign. A good engineer names two or three possibilities, says which they would check first and why, then says plainly they cannot be certain until they look. Total certainty about an unexamined fault, especially when it lands on the most expensive cause, means the conclusion came before the evidence. A flat refusal to discuss it at all usually means nobody technical is on the call.
What should I do if a plumber pressures me to decide immediately?: Stop and take a day. Genuine emergencies are uncontrolled water, a smell of gas, scalding water at a tap or a discharge pipe running constantly from an unvented cylinder, and those should be made safe before money is discussed at all. Anything else can wait overnight. Ask for the diagnosis in writing naming the component that has failed, pay for the attendance you agreed, and get a second opinion before committing to a replacement.
Do bad reviews mean I should avoid a plumber?: Read the replies rather than counting the stars. A firm that answers a complaint with specifics, dates and what it did next keeps proper job records, which is exactly what you want when something goes wrong. A firm that answers with an accusation against the customer is showing you how a dispute with you would go. A perfect average made of short, generic entries tells you less than three detailed reviews describing an actual fault.
Is a cheap quote a warning sign?: A low figure offered instantly, before anyone has asked what system you have or what the symptom is, is a booking tactic rather than a quote. It relates to nothing, and it usually grows once the job has been opened up. Being asked for the make, the model, the postcode and the symptom before any number appears is the better sign, because then the figure is attached to something real that can be checked later.
What paperwork should I insist on before hiring someone?: Before the visit, the charging structure by text or email. After the work, an itemised invoice naming the component that failed, parts listed separately from labour, the rate or fixed fee applied, and the business and engineer details. Gas work carries its own safety documentation, and an unvented cylinder service should produce a record of the checks and readings. Without that record a warranty claim, an insurance claim or a second opinion becomes much harder.