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Almost every page that ranks in the UK for water leak detection is selling something. The top of the results is a block of leak detection companies whose business is a paid survey, and the organic results underneath are water company help pages whose job is to stop water being wasted. Both are useful. Neither of them answers the question with real money attached, which is whose pipe the leak is on and who pays to put it right.
Two things are worth knowing before you call anybody. The first is that the standard meter test, run twice with one change in between, separates an internal leak from a leak on the buried supply pipe outside. That distinction changes who is responsible. The second is that a lot of UK buildings insurance carries something called trace and access cover, which pays for finding a leak rather than repairing it, and most people have no idea it is in their policy.
I spent sixteen years running plumbers merchants across the south of England. I am not a plumber and I have never held Gas Safe registration, so nothing here is a first-hand repair account. What the counter does give you is a pattern: people turning up to buy pipe, fittings and compression olives for a leak they had not actually located yet, and coming back two days later for more because they had opened up the wrong wall.
Start with the meter test, because it costs nothing
This is the single most useful thing on this page and it is why it sits at the top rather than after a shopping list. If you are on a water meter, you can establish in about half an hour whether water is leaving your system when nothing is using it. No tools, no survey, no appointment.
This is the same test published by United Utilities, Yorkshire Water and most other suppliers, so it is not controversial. What they mostly leave out is the second half.
The second reading tells you which side of the boundary the leak is on
Run the test again, identically, with one change: turn off your internal stop tap first. That is the isolating valve where the mains enters the house, usually under the kitchen sink, sometimes in a downstairs cloakroom or under the stairs. With it closed, no water can reach anything inside the building.
Two cautions. Some older properties have the stop tap in an awkward place, and a stop tap that has not been turned for twenty years can seize or, worse, fail to reseal afterwards. If it will not move easily, leave it. And if you cannot find your stop tap at all, that is worth fixing before an emergency, which is covered in the guide on what to do when there is no running water.
Who pays for a supply pipe leak in England and Wales
This is the part the detection companies skate over, because it is not their bill. The general position across suppliers in England and Wales is that the water company owns the pipe up to the property boundary and the property owner owns the pipe from the boundary into the house, including the section under the garden and the drive. It is not identical everywhere, so check your own supplier, but the published wording is consistent.
The practical order, then, is: run the meter test, run it again with the stop tap closed, and if it points at the supply pipe, phone your water company before you phone anyone else. Getting the leak logged with them starts the clock on any allowance, and some will come and confirm it at no charge. If the bill has already landed, the guide on reducing your water bill covers how usage is charged and what a normal figure looks like.
Which symptom you have decides what to check next
Leaks announce themselves in a small number of recognisable ways, and each one points somewhere different. Find your symptom before you start lifting floorboards.
What you can genuinely find yourself
The toilet, first, every time
Put a dye tablet in the cistern, or a few drops of food colouring, and leave it thirty minutes without flushing. Colour appearing in the pan means water is passing the flush valve continuously. The other version needs nothing at all: lay a dry strip of toilet paper against the back of the dry pan and come back in half an hour, as Anglian Water describes. Wet paper, leaking valve.
Also check the overflow. Older installations have an external overflow pipe through the wall, so a dripping pipe outside the bathroom window is a float valve problem, not weather. Modern close coupled toilets usually overflow internally into the pan instead, which is tidier and completely invisible, which is exactly why they get missed.
Under the sinks and behind the appliances
Dry every pipe and joint under the kitchen and bathroom sinks with kitchen roll, then run the taps hard and fill the basin and let it out in one go. Waste leaks often only appear under a sudden volume, not a trickle. Do the same behind the washing machine and dishwasher, checking the fill hose connection and the rubber washer inside it, which perishes and is a couple of pounds to replace.
Rusty staining on a compression joint, green crusting on copper, or a white salty bloom on a soldered joint all mean water has been present, even if it is dry today. That is the kind of thing worth photographing before you decide nothing is wrong.
Around the bath, the shower tray and the tiling
A bathroom leak is often not a pressurised pipe at all, which is why the meter test can come back clean while the ceiling below still stains. Water that only escapes while the bathroom is being used points at a seal, a waste or the tiling rather than a supply pipe, and those are checked a different way.
The bath. Fill it to the normal level, mark the water line and leave it an hour without touching it. A dropping level means the waste or the plug seating is passing. Then get the bath panel off and look underneath while somebody fills it and lets it out in one go, because the overflow connection and the trap joints usually only leak under a full discharge rather than a trickle. An acrylic bath also flexes when somebody stands in it, so a seal that is sound on an empty bath can open on a loaded one.
The shower tray. Look for a hairline crack in the tray, most likely where it is unsupported or has been fitted without the manufacturer's cradle, and check the joint where the tray meets the tiling as well as the tray itself. A tray that moves underfoot will keep breaking whatever sealant you put on it, so stopping the movement comes before resealing it again.
The sealant and the grout. Mould along a silicone line is a symptom rather than a cause: it grows where water is sitting in a gap. Run a fingernail along the whole joint and find anywhere the bead has lifted from the tile or the bath edge, because a line that is perfect for most of its length and open for a short stretch is still a leak. Grout that has gone soft or disappeared in a shower lets water behind the tiles, and that shows up at the bottom of the wall or in the room below rather than where it went in.
The pan connector and the basin waste. The flexible connector between a toilet pan and the soil pipe leaks once the pan has rocked, so check it with somebody sitting on the pan rather than with the pan empty, and check whether the pan is actually fixed down. Under the basin, dry the trap and every joint with kitchen roll, then fill the basin and pull the plug, for the same reason as the bath.
The radiator or towel rail. A bathroom is a damp room, so a radiator in one corrodes faster than the same radiator elsewhere in the house, and a pinhole weep leaves a rust stain rather than a puddle. A leak here will not move the water meter at all, because it is on the heating circuit rather than the mains, which is worth knowing before you conclude from a clean meter test that nothing is leaking.
One general point that saves a lot of pointless work. If the stain in the room below only appears after somebody has showered, the supply pipework is almost certainly fine and you are looking for where water is getting past a seal. If it is there whether the bathroom has been used or not, it is a pipe.
A moisture meter on a suspect wall
A cheap pinless moisture meter will not tell you where a leak is, but it will tell you which of two walls is wetter and roughly where the wet area stops. That is often enough to decide whether to open something up. Take readings in a grid and compare them against a wall you know is dry, because the absolute number on a sub-£25 meter means very little on its own. Salts in old plaster can also read as damp when the plaster is bone dry, so treat a high reading as a reason to look closer, never as proof.
Where the DIY route ends
Being honest about this is the point of the page. A leak on a pipe cast into a concrete floor, or buried two feet down under a driveway, cannot be found by looking. The professional methods exist precisely because there is no visual route to the answer.
| Method | What it does | Where it is used |
|---|---|---|
| Acoustic detection | Ground microphones and correlators listen for the noise a pressurised leak makes escaping through a pipe wall | Buried supply pipes, pipes under solid floors |
| Thermal imaging | Shows temperature differences through a surface, so a hot pipe leaking under screed appears as a warm line | Underfloor heating, hot water pipes in floors, wall voids |
| Tracer gas | A hydrogen and nitrogen mix is put into the drained pipe and a detector picks up where it escapes through the floor | Small leaks acoustics cannot hear, plastic pipe, cold pipes |
| Moisture mapping | Systematic meter readings across a floor or wall to map the wet area and narrow the search | Deciding where to open up, and documenting a claim |
On cost, be careful with any number quoted without a survey. Checkatrade's own listing for water leak detection services displayed a price range of £115 to £234 when checked on 18 September 2026, which is a reasonable indication of a straightforward domestic visit. Excavation, reinstatement and the repair itself are separate and are where the real money goes. A firm quoting a fixed price down the phone for a leak nobody has looked at is guessing.
Check your insurance for trace and access cover before you pay
Trace and access is the clause that pays for finding a leak and for making good the damage caused by the search, rather than for repairing the leak itself. It is worth reading your own policy wording carefully, because the two consumer sources checked here describe it slightly differently, and the difference matters.
Confused.com describes trace and access as a home insurance feature that pays for the cost of finding the source of a hidden water leak and making it accessible for repair, including repairs needed to fix damage caused by the search. It says the cover is usually part of a buildings insurance policy, that policies generally cover up to £5,000, and that it does not pay for repairing the leak itself.
Compare the Market puts it less definitely: some home insurance policies include trace and access cover and others do not, so you should check your policy, and if it is absent you should be able to add it for a fee. It gives a typical limit of between £5,000 and £10,000 and confirms it does not usually cover repairing the leak or the damage it caused.
Both checked on 18 September 2026. Take the disagreement seriously: do not assume you are covered and do not assume you are not. Find the words "trace and access" in your policy schedule, or ring the insurer and ask, before you instruct anybody.
Two practical points follow from that. Ring the insurer before you commission a detection survey, because some policies require you to use their own approved contractor and will not reimburse a firm you chose yourself. And keep every photograph, meter reading and invoice, because a claim for finding a leak is a claim about a thing that is now hidden again behind new plaster.
Kit that is genuinely worth owning
Very little of this is expensive, and none of it replaces a professional survey on a buried leak. The honest split is that the first three items help you find or confirm a leak, and the last two stop one making a mess while you arrange a proper repair. Prices are not shown for Amazon items, because Amazon only permits prices to be published through its own feed.
| Item | What it tells you or does | What it will not do |
|---|---|---|
| Dye tablets | Confirms a toilet cistern is passing water into the pan | Nothing outside the bathroom |
| Pinless moisture meter | Compares wet and dry areas of a wall or floor | Locate a pipe, or prove the moisture is a leak |
| Smart water leak alarm | Shouts the moment water touches the floor under a sink or appliance | Detect anything inside a wall or under a screed |
| Self-amalgamating tape | Holds a pinhole or weeping joint for hours or days | Serve as a permanent repair |
| Pipe repair clamp | Seals a burst or punctured pipe under pressure so you can restore the water | Fit a joint, bend or fitting, only a straight run |
Best for checking a suspect wall
RDINSCOS Pinless Moisture Meter
- Pinless sensor, so no holes in the plaster
- Four material modes including wall and masonry
- Backlit display with a three colour damp scale
- Battery powered and pocket sized
Pros
- Non destructive, which matters on a wall you may not need to open
- Cheap enough to be worth owning before you need it
- Good for comparing a suspect wall against a known dry one
Cons
- Pinless meters read only a shallow depth, so a leak deep in a wall can read normal
- Salts in old plaster can produce a high reading with no water present
- The absolute number is close to meaningless, only the comparison is useful
Judged on specification and manufacturer documentation rather than hands-on testing. Buy it to compare readings across a surface, not to prove a leak exists. Used that way it will tell you where to start looking and, just as usefully, where not to.
Best early warning under a sink
TP-Link Tapo T300 Smart Water Leak Sensor
- Six detection probes on the top and bottom faces
- 90dB local alarm that sounds without any hub or network
- IP rated body suitable for a damp cupboard or under an appliance
- Battery powered with no wiring
Pros
- The local siren works on its own, which is the part that actually saves a floor
- Small enough to sit behind a washing machine or in a cupboard base
- Sensible price for something you will buy several of
Cons
- Phone notifications need a Tapo hub, which is an extra purchase and is not always made clear on the listing
- Only detects water that reaches the floor, so it is useless for a pipe inside a wall
- One sensor covers one spot, so realistic coverage means buying a few
Judged on specification and manufacturer documentation rather than hands-on testing. This is damage limitation, not leak detection. Put them where a slow failure would do the most expensive damage: under the washing machine, under the dishwasher, in the airing cupboard and under the kitchen sink.
Best for stopping a leak right now
Kibosh Emergency Pipe Repair Clamp (22mm)
- Fits around a leaking pipe and clamps shut by hand
- This listing is the 22mm size, for metal, plastic and multi-layer pipe
- Reusable rather than single use
- No tools required to fit
Pros
- Gets the water back on while you arrange a proper repair
- Works on plastic and multi-layer as well as copper
- Keeps its shape, so it lives in a drawer for years and still works
Cons
- Straight runs of pipe only, so no joints, bends or fittings
- Explicitly a temporary repair and should not be left in place
- Sold per pipe diameter, so measure your pipe before ordering rather than after
Judged on specification and manufacturer documentation rather than hands-on testing. This was one of the things fitters bought without being asked, because the alternative on a Friday afternoon is a house with the water off all weekend. Buy the size that matches your pipework before you need it.
Two consumables complete the set. Blue Streak dye tablets turn the toilet test into a five second job, though the professional tub holds far more than a household will ever use, so a small pack is the sensible buy if you can find one. Self-amalgamating tape bonds to itself rather than to the pipe, which is why it holds on a wet surface where ordinary tape slides off. It buys hours, not months.
Check Blue Streak dye tablets on AmazonCheck self-amalgamating tape on AmazonBoth are cheap enough to keep in a cupboard before you need them, which is the only time either is any use.
Outside Amazon, B&Q listed the Aqara Water Leak Sensor T1 at £19.99 when checked on 18 September 2026, which is worth knowing if you already run Aqara or Apple Home and do not want a second app. Screwfix and Toolstation both stock stopcock keys and pipe repair clamps over the counter, which is the fastest route when something is actively leaking, though both block automated price checks so no figure is published here.
If you are building a basic kit from nothing, the list in the DIY plumbing tools guide covers the rest, and the piece on stopping pipes freezing and splitting is the one to read before winter rather than during it.
Frequently asked questions
What is the easiest way to find a water leak?
Read your water meter, use no water for 30 to 60 minutes, then read it again. If it has moved, water is escaping. Repeat the test with the internal stop tap closed: if the meter still moves, the leak is on the buried supply pipe outside, and if it stops, the leak is inside the house.
How can I check if my house has a water leak for free?
The meter test costs nothing. So does the toilet paper test on every toilet in the house. If you are not metered, ask your water company to fit one, which is normally free, and ask at the same time whether they will investigate a suspected leak. Several will attend at no charge before you have spent a penny with a private firm.
What is the most common water leak in a house?
A toilet passing water from the cistern into the pan. It makes no puddle, often makes no noise, and can run for months. It is also one of the cheapest things on this list to put right, usually a flush valve seal or a float valve adjustment.
How do plumbers find hidden leaks?
By isolating sections of pipework and watching the meter, then by acoustic listening equipment, thermal imaging or tracer gas where the pipe is buried. A general plumber will usually isolate and eliminate. A dedicated leak detection firm brings the acoustic and thermal kit, which is what you are paying the survey fee for.
How do you find a water leak that is not visible?
Work by elimination rather than by looking. Establish with the meter that water is leaving the system, establish with the stop tap whether it is inside or outside, then isolate what you can: close the valves feeding a bathroom, or drain and isolate the heating circuit, and see whether the loss stops. Each isolation halves the search area.
Does home insurance cover leak detection?
Often, through the trace and access clause, but not universally. Confused.com describes it as usually part of a buildings insurance policy with a typical limit around £5,000, while Compare the Market says some policies include it and some do not and that it can often be added for a fee. Both agree it pays to find the leak and make the area accessible, not to repair the leak. Read your own policy schedule rather than relying on either summary.
What is the average cost of leak detection in the UK?
Checkatrade's listing for water leak detection services showed a range of £115 to £234 when checked on 18 September 2026. Treat that as the cost of somebody attending and locating, not of excavating, repairing or reinstating a driveway. Anyone quoting a total before they have seen the property is estimating.
Can a leak cause low water pressure?
A large leak on the supply pipe can, because water is being lost before it reaches the house. Most low pressure has duller causes though, including a partly closed stop tap, a blocked filter or simply a low incoming main. Eliminate those before assuming the worst.
Related guides
- Why your boiler keeps losing pressure, for when the water going missing is on the heating side rather than the mains.
- Troubleshooting water pressure, to rule out the ordinary causes before you blame a leak.
- Dealing with frozen pipes, because a pipe that froze in January is the pipe that splits in February.
- Tips to reduce your water bill, for working out whether your usage is genuinely abnormal.
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