Choose a leak detection company that confirms the leak and pinpoints it with non-invasive methods before it cuts into anything, uses more than one method, and gives you a written report with photos and readings that your insurer will accept. The best choice can also repair the pipe on the same visit and explain exactly what has to be opened up and made good, so you are not paying two firms to do one job.

First, check that you really have a leak

Before you book anyone, a few simple checks tell you whether water is escaping and roughly where. They also help the engineer, because a clear history speeds up the search.

1. Do a meter test. Turn off every tap, and make sure the washing machine, dishwasher and toilets are not filling. Read the water meter, wait 30 minutes without using any water and read it again. If the number has moved, water is going somewhere.
2. Watch the boiler pressure. If your combi or system boiler keeps losing pressure and needs topping up, the leak is probably on the heating side rather than the water supply. Our guide to a boiler that keeps losing pressure explains the other causes.
3. Look for the signs. Damp patches, lifting floor tiles, a warm spot on a solid floor, mould behind furniture, a musty smell or the sound of running water when nothing is on.
4. Note when it happens. A stain that only grows after someone showers points to the shower tray, seals or waste, not the pipework. A leak that appears when the heating is on points to the heating circuit.

If you can see water coming through a ceiling or near electrics, deal with that first (see the warning box below) and treat it as an emergency.

The methods a good leak detection company should use

No single tool finds every leak. A thermal camera needs a temperature difference to work, and acoustic equipment hears a pressurised leak on copper far more easily than one on plastic pipe. A company that turns up with one gadget and a lot of confidence is guessing. This is how the main methods compare.

Method	How it works	Best for	Limits
Meter and pressure testing	Isolates sections of pipework and watches for a pressure drop	Proving there is a leak and narrowing it to one circuit	Tells you which pipe run, not the exact spot
Thermal imaging	A camera shows heat patterns through floors and walls	Hot water and heating pipes, especially in solid floors	Needs a temperature difference, so cold mains leaks can be hard to see
Acoustic listening	Ground microphones and contact probes pick up the sound of water escaping under pressure	Mains supply pipes and pressurised copper	Weaker on plastic pipe and in noisy surroundings
Tracer gas	A harmless gas mix of hydrogen and nitrogen is pushed into a drained pipe and detected where it escapes	Plastic pipe, underfloor heating and pipes under screed or outside	The pipe has to be isolated and drained first
Moisture mapping	Meters read moisture across walls and floors to map how the damp spreads	Finding the source rather than where the water shows	Water travels along joists and pipes, so readings need interpreting
Endoscope camera	A small camera goes through a tiny hole or an access point	Looking into voids, boxing and under baths	Only sees what the lens can reach

The usual tracer gas is a mix of about 5 per cent hydrogen in nitrogen. At that strength it is not flammable, and hydrogen is so small and light that it finds its way up through concrete, screed and soil to the point of escape, where a detector picks it up.

Our article on how plumbers find hidden leaks without digging up your floor goes into each method in more detail. When you speak to a company, ask which of these it will bring for your leak and why. A clear answer is a good sign. At Vantage, our leak detection service starts with non-invasive methods and only opens up once the leak has been found.

Trace and access: how insurance fits in

Many buildings insurance policies include trace and access cover as part of escape of water. It is designed to pay for finding a hidden leak and for opening up and making good the floor or wall to reach it. Policies vary, so check three things before you book:

• The limit. Trace and access usually has its own limit, separate from the main escape of water cover.
• The excess. Escape of water claims often carry a higher excess than other claims.
• What is excluded. Some policies pay to find the leak and repair the damage but not to replace the failed pipe or fitting itself. Wear and tear and failed shower seals are common exclusions.

Ring your insurer before work starts. Some insurers want to appoint their own contractor, and others will let you choose but want a report and an itemised invoice afterwards. Take photos of any damage before anything is moved. Our page on trace and access explains how the find and the repair fit together.

What the report should include

The report is what your insurer relies on, so a good company writes it to be read by a claims handler, not just by another plumber. It should show:

• the property address, the date and who carried out the survey
• the symptoms you reported and what the engineer found on arrival
• each method used, with readings or images (thermal images, moisture readings, pressure test results)
• the location of the leak, marked on a photo or a simple plan
• the cause, such as a failed joint, a nail through a pipe or a split fitting
• what was opened up to reach it, and what making good is needed
• the repair carried out, or the repair recommended if it could not be done on the day

Questions to ask before you book

These questions separate a firm that finds leaks from one that just breaks things open until it gets lucky.

1. Which methods will you use for my leak, and why? The answer should change depending on whether it is heating, hot water or the cold mains.
2. Will you locate the leak before lifting or cutting anything? The answer should be yes, apart from small inspection holes where a camera is needed.
3. Can you repair it on the same visit? A company that only finds leaks leaves you booking a second trade. A plumber with a fully stocked van can often fix it straight away.
4. What will the report include, and when will I get it? Ask to see an example.
5. How do you charge, and what happens if the leak is hard to find? You want to understand the charging before anyone arrives.
6. Who will do any work on the boiler or heating? Refilling and restarting a heating system after a repair may involve the boiler, and any work on a gas appliance must be done by a Gas Safe registered engineer.
7. What guarantee comes with the repair? Ask how long, and whether it covers labour.

Red flags to avoid

• Lifting floors or breaking tiles before any testing has been done.
• One method only, whatever the leak.
• No written report, or a one-line invoice that just says “leak found and fixed”.
• A recommendation to replumb the house or rip out the shower before the leak has been located.
• A chemical leak sealer poured into the heating as the first answer. It is not a diagnosis, and on some systems it can cause problems of its own.

Leak detection specialist or a plumber?

Some leak detection firms only locate leaks. They are good at the find, but you then need a plumber for the repair and possibly a builder for the making good. A plumbing company that carries the detection equipment can find the leak, repair the pipe and restore the heating system in one visit, and write a single report covering all of it. For most homes that is simpler and quicker. For large commercial sites or very long underground supply pipes, a specialist may be the better fit, and a good plumber will tell you so.

What it costs with Vantage

In normal working hours there is no call-out fee. After the first hour, time is charged in half-hour steps, and parts are quoted before we fit them. Evening, weekend and overnight visits are charged at the out-of-hours rates. Every rate is published on our prices page, so you know what you will pay before we arrive. If your policy includes trace and access, we write the report so you can send it straight to your insurer with the invoice.

Frequently asked questions

Is leak detection covered by home insurance?

Often, yes. Many buildings policies include trace and access cover under escape of water, which pays to find a hidden leak and to open up and make good. Check the limit, the excess and the exclusions, and speak to your insurer before work starts.

Can a leak be found without damaging floors or walls?

In most homes the exact spot can be found without breaking anything, using a combination of pressure tests, thermal imaging, acoustic equipment, tracer gas and moisture mapping. Some opening up is usually needed to repair the pipe, but a good find keeps that to a small, neat area.

How long does leak detection take?

A straightforward leak in an accessible area can be found in an hour or two. Leaks under solid floors, in underfloor heating or on long outside supply pipes can take longer because each section has to be isolated and tested.

Who is responsible for a leak on the water supply pipe?

Inside your home the pipework is yours. Outside, the supply pipe from your property boundary to the house is usually the owner’s responsibility, while the pipe up to the boundary is the water company’s. Your water company can tell you where its responsibility ends at your address.

What if the leak is on the heating system?

A heating leak usually shows as a boiler losing pressure. The engineer isolates the heating circuit, pressure tests it and uses thermal imaging or tracer gas to pinpoint the leak, then repairs it and refills and repressurises the system.

Leak detection in Hertfordshire, Bedfordshire and Cambridgeshire

If you have a hidden leak, a rising water meter or a boiler that keeps losing pressure, our engineers can find it, repair it and give you a report for your insurer. See our leak detection service or call 01462 506374. The phone is answered 24 hours a day, 7 days a week, and we offer 24/7 emergency cover for leaks that cannot wait.