Why Are Leak Detection Quotes So Different in London?

If you have rung round three or four 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 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 one thing that matters: the total fixed price to actually find your leak.

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.

Hourly versus fixed fee: the biggest fork in the road

Most of the confusion comes down to this one choice. An hourly model and a fixed-fee model answer the same question in opposite ways.

How hourly pricing behaves

With an hourly rate, 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.

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 hourly quote is not a price, it is a starting point.

How fixed fees behave

A fixed fee flips the risk. You agree one number up front, and the company absorbs the uncertainty about how long the job takes. If your leak turns out to be awkward, that is their problem to solve within the agreed price, not a reason for the bill to grow.

The honest position, and the one we take, is a fixed fee agreed at the point of booking. For a typical London home that sits in the region of £250 to £450 for a complete survey, confirmed before anyone is dispatched. You know the figure in advance, and it does not move because the leak was stubborn.

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". Company B quotes a fixed £350 for a complete multi-method survey, confirmed in writing at booking. On paper, Company A looks like less than a quarter of the price. Here is how the two actually play out once an engineer is on site.

The headline that looked four times cheaper ends up costing more than the fixed fee, and the tenant had no way of knowing that when they booked. The rate quoted never changed. The number of hours, the extra method, the report and the add-ons all did. 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 fixed fee is the only quote that tells you the real number 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 total fixed price. One figure to locate the leak, agreed now, not an estimate 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 a total 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 cap.

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, ignore the headline and reduce every quote to one figure: the total fixed price to locate the leak, including everything needed to do that. Ask each company the same set of questions.

• Is this a fixed total, agreed now, or an estimate that can change on site?
• 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?
• Is there a no find, no fee guarantee?

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 clear fixed fee for a complete multi-method survey 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 to. The fee is fixed and agreed when you book, not invented once an engineer is on your doorstep. For a typical London home that is usually £250 to £450 for a complete survey. 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 do not pay. 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 number to grow, because it cannot.

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 total fixed price for a complete survey, the comparison becomes simple, and the leak becomes a great deal easier to fix.