Leak detection and repair

Where leaks in the home come from

Water takes the path of least resistance. It can run for metres along a joist or pipe before it shows up anywhere, so the damp patch you see isn't necessarily directly above or next to the leak. That's why leak detection starts with two questions: which pipes run nearby, and what kind of water is it?

Water supply pipes and joints

Many leaks start at a connection: a compression fitting that has vibrated loose, a soldered joint that finally gives out after years, or the connection to a tap behind the washbasin. Older copper pipes can also corrode from the inside, leaving tiny pinholes. Because the water supply is always under pressure, a spot like that leaks day and night, even when nobody is using any water.

Waste pipes, sealant and sanitary ware

A waste pipe isn't under pressure and only leaks when water runs through it. Typical culprits are a cracked strip of sealant along the shower tray, a leaking trap under the washbasin or a loose connection between the toilet and the waste pipe.

Harsh drain cleaners sometimes play a part too. They get hot and attack rubber seals and older pipes, so a drain that was merely blocked ends up leaking as well. That's why we advise against them.

Central heating pipes and underfloor heating

Can you feel a warm, damp spot on the floor, or do you keep having to top up the central heating boiler because the pressure drops? If so, the leak may be in the heating system rather than the water supply. A thermal camera is a useful tool here, because warm pipes light up clearly on the screen.

Signs of a hidden water leak

A leak you can see is usually found quickly. The trickier kind is the one going on behind tiles, inside a floor or above a ceiling. Look out for these signs:

• a ring or damp patch on the ceiling, often below the bathroom or kitchen
• paint that flakes, wallpaper that peels or plaster that feels soft
• mould or a musty smell in a spot that's normally dry
• tiles or skirting boards coming loose, or a wooden floor starting to bulge
• a rushing or hissing sound in the wall when no tap is running

The water meter test

If you're not sure, try this simple test. Turn off all the taps, switch off the washing machine and dishwasher, and wait until the toilet cistern has filled. Note the reading on the water meter in the meter cupboard, don't use any water for an hour, then check it again.

If the reading has changed, or the smallest dial is still turning, water is escaping somewhere. That could be a leaking pipe, but it might also be a toilet that keeps running without you noticing.

First aid: what you can do yourself

If you can see water running or dripping, the first few minutes decide how much damage is done, both in your home and at the neighbours'.

1. Turn off the main stopcock. It's usually in the meter cupboard, next to the water meter.
2. If water is reaching lights, sockets or appliances, switch off the relevant circuit at the fuse box in the meter cupboard.
3. Put down buckets and towels, and move furniture, rugs and electronics out of the way.
4. Take photos of the damp patch and the damage.
5. Warn the neighbours below or next door and, if you live in a flat, the owners' association (VvE) or the property manager as well.

What to leave alone

Don't start knocking off tiles or poking holes in a ceiling to find the leak yourself. You risk hitting pipes or wiring, and chances are you'll be looking in the wrong place anyway. And keep clear of a ceiling that is sagging or bulging.

If there's no obvious source, if the water meter keeps running while everything is off, or if the water is coming through a ceiling shared with the neighbours upstairs, call us. At that point acting quickly matters more than trying to puzzle it out yourself.

Leak detection: how the plumber finds the source

We carry out leak detection step by step, with measuring equipment rather than a sledgehammer. The aim is to pinpoint the leak as precisely as possible, so that, at most, a small opening is needed.

First, the plumber uses a moisture meter to map how far the damp has spread through the wall, floor or ceiling. The wettest point often tells you more than the visible stain.

A thermal camera then shows the hot and cold pipes behind tiles and plaster; a leaking hot water pipe often shows up as a distinct warm spot. A pressure test involves isolating a section of pipe and pressurising it. If the pressure drops, that confirms the leak is in that section. If a waste pipe is the problem, a drain camera inspection can provide the answer.

From finding the leak to fixing it

Once the source has been found, you'll naturally want the leak fixed as well. The plumber usually replaces a leaking joint, a corroded bit of pipe or a broken trap during the same visit. If a longer section is affected or the leak is under a screed floor, we'll arrange a water pipe repair in consultation with you. If the real cause is a shower that keeps overflowing and pushing water past the sealant, we deal with that too by unblocking the shower drain and resealing the joint.

Limiting the damage: neighbours, owners' association and insurance

A leak rarely affects only your own home. Water runs downwards, so in a walk-up or a block of flats the neighbours below often suffer just as much. Let them know what's going on, even if the leak has already been found. If a shared pipe is involved, such as a soil stack, that's often a matter for the VvE, so report it to the property manager as well.

It helps to give your insurer three things: photos of the damage, when you discovered it, and a description of the cause. You'll get that last one from the plumber. Whether tracing the leak and the repair are covered differs from policy to policy. If you rent, get in touch with your landlord as well.

What leak detection costs, including outside office hours

At Spoed Loodgieter Breeman, simple jobs start from €89. The call-out charge isn't included. Because some leaks are found quickly and others take longer, we first give you a price estimate over the phone, based on your description.

If it's already clear that it's a bigger job, such as a leak in a pipe duct or under a tiled floor, you can ask for a quote. That way you know where you stand before anything starts.

A leak in the middle of the night

Water doesn't keep office hours. A burst washing machine inlet hose or a leak coming through the ceiling on a Sunday night won't wait until Monday. That's why we're available 24/7, including public holidays. Outside office hours we charge an out-of-hours rate, and we'll tell you what it is before anyone sets off.

If the main stopcock is off and the situation is stable, we'll decide together whether a plumber needs to come straight away or whether the next morning will do.

Preventing leaks

Not every leak can be prevented, but many can:

• Once a year, check the sealant around the bath, shower and kitchen worktop, and replace any cracked sealant in good time.
• Every now and then, look in the cupboards under the kitchen sink and washbasin to check that the trap and hoses are dry.
• Turn off the washing machine tap when you go on holiday.
• Drain the outside tap before winter and insulate pipes in unheated spaces.

If a tap is dripping or leaking around its base, replacing or repairing the tap is far less trouble than water damage in your kitchen cupboard.

Leak detection in your area

Tracking down a leak in a canal house in Amsterdam is a different search from finding one in a walk-up flat in The Hague, a 1930s house in Haarlem or a family home in Zoetermeer. Our plumbers know the difference. Our locations page describes how homes were built in many more cities, though we work right across the country.

Suspect a leak? Call 085 115 0249 and have it traced before the damage spreads.