How a Leak Detection Visit Works, Step by Step

The five steps at a glance

Every visit follows the same outline, whatever the leak turns out to be. First you tell the team what you can see and you are given the price and the scope in writing. Second, the engineer arrives and listens to you and looks at the property before any instrument comes out. Third, the search runs as a ladder of methods, each one chosen on what the last one showed. Fourth, the leak is written up. Fifth, if a repair is wanted, it is quoted in writing and you decide.

The rest of this page takes the steps in order, and spends the longest on the third, because the decision to move from one method to the next is where a visit is won or lost. The detection price is one fixed price of £480, every method included, agreed before we attend, and what that means for each decision on the ladder is the point of the page. No VAT is charged.

If you want the methods described one at a time before reading how they are sequenced, the what is included page does that, and the pricing page sets the figure beside what is quoted separately.

Step one: you describe the leak and see the price

You start with the enquiry form. The most useful things to put in it are what you can see (a stain, a drip, a damp patch, a falling pressure gauge), where it is, when it started, whether it gets worse when a particular tap, appliance or the heating is on, and whether the water is still escaping. A photograph with the date helps, and the leak detection quote checklist lists the other things worth having to hand.

The team confirms the scope and the price in writing before attending. For a single domestic property in London the price is one fixed price of £480, every method included, agreed before we attend. If the property is something else, such as a commercial unit or a larger block, the scope and the figure are agreed in writing first, and the visit does not start until they are. No VAT is charged.

One practical piece of evidence is worth gathering at this stage. Close the stop tap, then read your water meter, wait twenty minutes with every tap and appliance off, and read it again. If the reading has moved, water is escaping somewhere on the property side of the meter, and you have a confirmed live leak. That also matters for the no find, no fee page, where the boundaries depend on whether a leak is confirmed live.

Step two: arrival, questions and a look around

The visit begins with a conversation and not with equipment. The engineer asks the questions you have already answered, and some you have not: when you first saw the damp, whether it comes and goes, whether anything was recently altered, where the stop tap and the meter are, and which neighbours share a wall, ceiling or riser with you. They then walk the property and look at the stain or symptom, the likely pipe runs, the appliances and the condition of the surfaces.

This part is not a formality. A damp patch below a bathroom is a different problem from the same patch below a kitchen, and a leak that appears only when the heating is running points at a different circuit from one that runs all the time. The more narrowly the engineer can frame the question before any instrument is switched on, the shorter the search.

If the water is running now and cannot be contained, the first job is to stop it, and the search follows. If anything smells of gas, everyone leaves the property and the National Gas Emergency Service is rung on 0800 111 999 before anything else happens.

Step three: the ladder of methods

The search itself works like a ladder. The engineer starts with the method that tells them most for the least disturbance, and steps up only when the evidence says to. A typical ladder begins with isolating and pressure testing circuits to find out which one is losing water, moves to acoustic listening and thermal imaging to narrow the area, uses moisture mapping to see which way the water is travelling, and then, if the position is still not certain, brings in tracer gas or an endoscope for the exact spot. Dye testing is used wherever the question is whether a particular fitting is the source.

Not every visit climbs the whole ladder. A leak under a bath panel might be settled by an endoscope and a moisture reading. A leak under a screed floor might need pressure testing, listening, a thermal pass and tracer gas. The engineer decides at each rung, and the decision is made on what the last method showed. No VAT is charged.

The decision to move up: why the price matters here

The decision at each rung is a judgement, and it is the part of the visit a customer cannot see. An engineer might stay on listening a little longer than needed because it is quick to do, or skip a slower method because a faster one looks plausible. Whether the judgement is made on what the leak needs or on what the clock reads depends a good deal on how the work is priced.

Under a time-based charge, every rung has a cost to you, and an honest engineer still faces the awkward position of recommending the slow, certain method that adds time. Under a rate card with equipment lines, the incentive can lean the other way, towards the method with the higher line. Neither is dishonest, and a good engineer behaves well under both. But the customer is left wondering whether the next step is for them or for the invoice.

Here that question does not arise. The detection price is one fixed price of £480, every method included, agreed before we attend, so a step up the ladder adds nothing to your bill and a step skipped takes nothing off it. The engineer has no reason to stop early with a plausible answer and no reason to prolong a search that is already settled. What remains is the thing you hired them for: reaching the right answer by the shortest honest route. No VAT is charged.

It also runs the other way. The price does not shrink when the leak is easy, and the team accepts that. A visit that is settled quickly costs the same as one that takes the full ladder, which is the fair counterpart of the risk the team takes on a difficult one.

When the search is difficult

Some leaks are hard. A slow weep inside a solid floor, a joint behind a fixed panel, a pipe that runs under a concrete slab and loses water into the ground: these can take every rung and some patience. When that happens, the engineer tells you what has been ruled out and what has not, and what the next rung would be. Nothing about the price changes.

Occasionally the search ends without a position for a leak that is plainly live. That is the situation the no find, no fee wording is written for, and it has a precise boundary: No find, no fee waives the detection fee only when a live leak inside your own property cannot be located. The other two outcomes, a leak that proves to be elsewhere and a survey that establishes no leak exists, are charged at the detection price and are explained on the no find, no fee page.

Whatever the outcome, you are told it in plain words before the engineer leaves, along with what the evidence is. No VAT is charged.

Step four: what you are given at the end

The visit ends with a written report. It says why the engineer attended, what methods were used, what was found and where, how it was confirmed, and what the readings were. Where a photograph shows the finding, it is in the report. It is part of the price and is not billed again.

The report is written to be used. You can send it to a landlord, a managing agent or a neighbour who owns the source. You can send it to your insurer: whether your policy covers anything is decided by your insurer, and the policy wording decides, but the report gives them accurate findings to work from. The insurance guides explain the questions to ask. No VAT is charged.

A good report also says what it cannot tell you. If a section of pipe was not accessible, or a method could not be used, it says so. A confident report that hides its gaps is worth less than one that names them.

Step five: the repair, if you want one

A small fix, such as tightening a fitting or changing a small part, can be done on the spot once the leak is found, and is quoted first. For a longer repair the leak is stopped first, and the repair is quoted in writing after that. The repair is a separate piece of work with its own written quote, and the figure for labour is stated in it: repair work is quoted separately in writing before it starts, as one fixed price with labour, parts and materials set out. No VAT is charged.

If the leak is under a floor or behind a wall, the quote also says how much needs to be opened and what making good involves. Making good, such as walls, ceilings and decorating, is quoted per job by a partner team. None of this is compulsory. You can take the report and use another contractor, or use none while you talk to a landlord or an insurer. The detection visit stands on its own, and the report is yours either way.

If you are weighing whether to repair or replace the pipe, the blog guide on replacing the pipe or paying for detection sets out the trade-off.

What to prepare, in short

You can shorten the visit and sharpen the evidence with a few small things. Know where your stop tap and meter are and be able to reach them. Clear access to the area under the stain, under the bath and around the boiler cupboard if the symptom is near them. Note when the damp appears and what is running at the time. Tell the team about any recent plumbing work. If the flat above or next door is involved, mention it, because their access may matter.

The visit is for one property, so if the source turns out to lie outside it, the report is the document that makes the next conversation possible. No VAT is charged.

• Know where your stop tap and water meter are.
• Read the meter, wait twenty minutes with everything off, and read it again.
• Clear access to the affected area and likely pipe runs.
• Note when the damp appears and what is running at the time.
• Mention recent plumbing work and any shared walls, ceilings or risers.