Why Are Leak Detection Quotes So Different in London?

If you have rung round three or four water leak detection companies in London, you have probably noticed something confusing. One quote comes back at under a hundred pounds. Another lands somewhere in the middle. A third is well into four figures. You described the same damp patch, the same dropping boiler pressure, the same mysterious water bill, and yet the numbers look like they belong to completely different jobs.

You are not imagining it. Published UK trade cost-guide ranges for water leak detection stretch from around £80 at the very bottom to roughly £1,600 at the top for a single visit. That is not because some companies are honest and others are crooks. It is because those numbers are measuring different things. A £90 figure and a £900 figure can both be technically accurate and still describe wildly different levels of work, risk and finality.

This guide breaks down exactly what sits behind the spread, so you can read a quote properly, ask the right questions, and compare offers on the two things that actually matter: whether the rate you were given is guaranteed, and what you owe if the leak is never found.

The short answer: quotes measure different things

The single biggest reason quotes vary so much is that companies are not all pricing the same product. Some are quoting a call-out. Some are quoting an hour of labour. Some are quoting a fixed fee for a complete survey. And some are quoting a deliberately low headline number that is designed to climb once an engineer is standing in your kitchen.

Before you can compare anything, you need to know which of those you are looking at. A cheap number is only cheap if it includes everything the job actually needs. Very often, it does not.

The pricing models you will run into

Across London you will meet a handful of distinct pricing structures. Each one behaves differently once the work starts. Here is how they map out.

The trap is comparing a call-out fee from one company against a multi-method fixed fee from another and concluding the first is cheaper. It usually is not. It is just quoting a smaller slice of the same job.

Guaranteed versus open-ended: the biggest fork in the road

Most of the confusion comes down to one choice, and it is not hourly versus fixed. It is whether the number you were given is guaranteed, and what you owe if nobody finds the leak. Two companies can quote the identical hourly rate and be selling you opposite levels of risk.

How an open-ended quote behaves

When the rate is only a starting figure, you are buying time, not an outcome. That sounds fair until you remember that leaks are unpredictable. A leak under a solid floor, behind a tiled wall, or on a pipe run that snakes across the whole property can take a long time to isolate. Every hour of that is on your meter, and the rate itself can be revised upward once an engineer has decided the job is awkward.

The forums are full of people who were quoted a modest hourly figure and then watched the total balloon because the engineer needed longer than expected, or came back a second day. The rate never changed. The number of hours did. On community threads like r/DIYUK and the MoneySavingExpert boards, the recurring warning is the same: an unguaranteed quote is not a price, it is a starting point.

How a guaranteed rate behaves

A guaranteed rate closes both gaps. The figure is agreed before anyone travels and cannot be revised on your doorstep, whatever turns up behind the wall. Put genuine no find, no fee behind it and the second risk closes too: if the leak cannot be located, the hours spent looking are not billed at all. Between them, those two commitments cap the only things that can really hurt you.

The honest position, and the one we take, is a fixed hourly rate agreed at the point of booking: £170 an hour for standard leak detection, £200 an hour for heating, mains and trace-and-access work, quoted before travel and never exceeded on the day. A typical domestic survey runs two to four hours, which puts a standard survey at £340–£680 in total, and we tell you the expected hours when you book. The rate does not move because the leak turned out to be stubborn, and if we cannot find it you are not charged for the detection time at all, however many hours it took.

A worked example: the cheap hourly quote that balloons

The clearest way to see the difference is to follow the same job through two different pricing models. Imagine a first-floor flat with a slow leak somewhere behind a tiled bathroom wall. The tenant below has a spreading brown stain on their ceiling, and the boiler is losing pressure overnight. It is a real leak, but not an obvious one.

Company A quotes an attractive headline of around £75 for the first hour, at a typical London rate, and says it will "take it from there". There is no estimate of how many hours that might be, and no no-find-no-fee behind it. Company B quotes a guaranteed £170 an hour, confirmed in writing at booking and never exceeded on the day, estimates two to four hours for a survey of this kind, includes the written report, and backs the whole thing with genuine no find, no fee. On paper, Company A's opening figure looks like less than half of Company B's. Here is how the two actually play out once an engineer is on site.

It is worth being straight about what that table shows. On the day everything went reasonably well, the cheap headline did land lower. What the tenant bought with the saving is the part nobody mentions at booking. The figure they agreed to was £75, not £420, and the extra hours, the second method, the report and the travel were all decided after the van was outside. Had the engineer packed up at five o'clock with nothing to show, that £420 would still have been payable in full. Company B's exposure was knowable before anyone was dispatched: a rate that could not move, an estimate of two to four hours, and nothing at all to pay if the leak stayed hidden. This is the pattern people describe again and again on r/DIYUK and the MoneySavingExpert forums, and on the comment threads under trade cost guides: the hourly figure was accurate, it just was not the price of the job. A guaranteed rate, with the hours estimated and a real no-find promise behind it, is the only quote that tells you what you are actually exposed to before you commit.

Single-method versus multi-method surveys

The word survey is doing a lot of heavy lifting in most quotes, and it hides a huge difference in thoroughness.

A single-method survey uses one detection technique. That might be acoustic listening equipment, a thermal camera, a moisture meter, or tracer gas. Each of these is genuinely useful, but each also has blind spots. Acoustic methods struggle with very small leaks or noisy environments. Thermal imaging depends on a temperature difference being present. A moisture meter tells you where water has spread, not always where it came from.

Leaks are frequently found only when several methods are combined. Thermal imaging narrows the area, acoustic confirms the point, and tracer gas or a pressure test verifies it. A company quoting a very low fixed price is often quoting for one method. If that method draws a blank, you are back to square one, paying again for the next attempt.

A multi-method survey brings the full toolkit on the first visit and keeps going until the source is pinpointed. It costs more than a single-method visit on paper, but it is usually cheaper in reality because it finds the leak once rather than charging you three times to get there.

The hidden line items that grow a quote on site

Here is where the low headline numbers earn their keep for the company quoting them. A quote can look cheap because several unavoidable parts of the job have been quietly left out, ready to appear as extras once the engineer is in your home.

• Access and reinstatement. To find some leaks, a small section of floor, tile or plaster may need lifting. Ask whether the quote includes putting things back. Many do not, and the making-good bill arrives separately.
• The written report. If you need to claim on insurance, you need documentation. Some companies charge for the report as an add-on, so the survey price you were quoted does not actually get you the thing your insurer requires.
• Second visits. If the first method fails, a follow-up appointment can be billed as a fresh job with its own call-out.
• Congestion charge, ULEZ and parking. In central London these can be passed on. Reasonable, but ask so it is not a surprise.
• VAT. Always check whether the number you were given includes VAT. A price quoted before VAT is effectively 20 per cent higher than it looks.
• Minimum charges and rounding. An hourly quote with a two-hour minimum is not really the hourly rate you were told.

None of these are automatically dishonest. The problem is when they are omitted from the headline specifically so the first number sounds competitive, knowing the real total will be assembled once you are committed and the van is outside.

What a good quote should itemise

A quote you can trust does not hide behind a single number. It spells out what that number buys, so there is nothing left to negotiate once an engineer is in your home. Before you accept any price, check that it makes each of these things explicit rather than leaving them to be discovered later.

• The rate, and whether it is guaranteed. The figure agreed now, together with the number of hours they expect the job to take, not a starting price that can drift upward on the day.
• The detection methods included. Whether the survey is single-method or multi-method, and that the price covers using several techniques together if the first does not find it.
• What "found" means. That the job runs until the source is pinpointed, not until the first method has been tried once.
• The written report. Confirmation that documentation suitable for an insurance claim is part of the price, not a separate charge.
• Access and reinstatement. Whether lifting a section of floor or tile and making it good afterwards is included, or handled separately.
• VAT and travel charges. That the figure is inclusive of VAT and states any congestion, ULEZ or parking costs up front.
• The no-find position. What you owe, if anything, when the leak cannot be located.

If a quote covers all seven, you can compare it against any other quote with confidence. If it covers only one or two, the rest of the cost has not disappeared. It has simply been left off the page. If the lowest number in your inbox looks unbeatable, it is worth reading what a genuinely budget visit really ends up costing in our guide to the real cost of cheap leak detection in London.

How to spot a quote designed to grow

Some quotes are built to expand. You can usually tell before you book. Watch for these signals.

• A headline price that is dramatically lower than everyone else. If it looks too good, it is almost certainly pricing a fraction of the job.
• Vague language such as "from £X" or "starting at". The word from is a warning that the real number is higher and undefined.
• Reluctance to confirm the rate and the expected hours in writing. If a company will only commit once the engineer has "assessed the situation", the price is open-ended by design.
• A call-out or attendance fee quoted as if it were the survey price.
• No mention of what happens if the first method fails to find the leak.
• Diagnostics billed by the hour with no estimate of the hours and no no-find-no-fee behind them.

The common thread is uncertainty left deliberately open. A quote you cannot pin down before the visit is a quote that can grow during it.

How to compare quotes like-for-like

To compare fairly, stop looking at the headline and start pinning down what the headline is attached to. Three questions do most of the work, because they close the two gaps a low number hides behind. Ask each company the same set.

• Is this rate fixed, or can it rise once an engineer is on site?
• How many hours do you expect this job to take?
• What do I owe if you do not find the leak, and is that a genuine no find, no fee?
• Does it cover multiple detection methods, or just one?
• Does it include a written report suitable for an insurance claim?
• Does it include any access work and putting things back afterwards?
• What happens, and what does it cost, if the leak is not found on the first method?
• Is VAT included, and are there any call-out, congestion or parking charges on top?

Once you have those answers, the confusing spread usually collapses. The £90 quote reveals itself as a call-out with hourly diagnostics stacked behind it. The four-figure quote turns out to include a full day, extensive access work and reinstatement you may not need. And a guaranteed rate for a complete multi-method survey, with the hours estimated up front and no find, no fee behind it, sits sensibly in the middle, with nothing hidden behind it.

You can read our full breakdown of what drives these numbers in our London leak detection cost guide, see exactly what is included in our pricing, and learn how our surveys work on our leak detection in London page.

Our honest position on pricing

We price the way we would want to be priced. The hourly rate is fixed and agreed when you book, not invented once an engineer is on your doorstep: £170 an hour for standard leak detection, £200 an hour for heating, mains and trace-and-access work. For a typical London home a complete survey takes two to four hours, so £340–£680 in total, and we say so before we travel. That price covers a multi-method investigation, using several detection techniques together until the source is found, rather than one method and a shrug if it does not work.

We also work on a no find, no fee basis, so the risk of an awkward leak sits with us, not with you. If we cannot locate it, you are not charged for the detection time, however many hours we spent looking. That only works because we bring the full range of methods to the first visit and keep going until we have an answer. There is no incentive for the rate to creep, because it cannot move.

That is the real reason quotes across London look so different. Most of the spread is not about quality. It is about how much of the job the headline number is honestly including. Once you insist on a rate that cannot move and a straight answer on what you owe if nothing is found, the comparison becomes simple, and the leak becomes a great deal easier to fix.