How to find and fix leaks in your house

How to know if you have a water leak in your house

While some water leaks are easy to spot, others can stay hidden (especially if they’re underground) and can cause serious damage before you even know they’re there. You can find a water leak in your house, even if you can’t see any water, in the following ways.

Checking your water usage regularly

Check your water usage often so you can see any sudden increases that you can’t account for (such as having visitors or watering the garden more in hot weather), which could be a sign of a leak.

Sign up for an online account or ask your water supplier to send you monthly statements so you can keep an eye on the water you’re using.

Drops in your water pressure when using the shower or bath

Noticing a drop in water pressure when you’re filling the bath or taking a shower could be a sign of a leak. You can check by turning off all your fixtures, then turning one back on. If the pressure is higher than it was, it’s probably a leak.

Life hack: In a shower, low pressure can also be caused by a clogged showerhead, thanks to a build-up of limescale. Or, if your shower is over your bath, you could have a faulty shower/bath diverter. Try cleaning your showerhead using a limescale remover and check the shower/bath diverter to see if this makes a difference.

Monitoring when your hot water heater/boiler comes on

If your hot water heater or boiler is on almost constantly, you could have a leak in your hot water pipe. These will generally be underground and could be harder to find than other leaks.

Stained or bulging walls

If you spot bubbling paint, brown stains, or bulges on your walls or ceiling, there could be water leaking behind them. These signs usually show up slowly, so keep an eye out for any changes, especially in rooms with plumbing like kitchens, bathrooms, or laundry areas.

Unpleasant/musty smells

A musty or damp smell that lingers, especially in basements, under sinks, or behind appliances, could be a clue that there’s hidden moisture or mould caused by a slow leak. If you’ve cleaned thoroughly and the smell sticks around, it’s worth investigating.

Damp patches on your floor

Look out for pools of water or damp patches on your floor with no visible signs that there’s a leak in your ceiling. These spots can appear on tile, wood, or even carpet and usually won’t dry out on their own.

Hissing or splashing noises

Hearing hissing, splashing, or dripping sounds when everything’s switched off can be a giveaway. These noises often come from hidden pipes and are easiest to catch at night or when the house is quiet.

An increase in mould or water-loving insects

Finding mould in new places or spotting more insects like ants, silverfish, or cockroaches can be a sign of excess moisture. These bugs love damp environments, so an unexplained increase could mean water is leaking somewhere nearby.

Leak detection tool

If you don’t want to have to keep looking for signs of a leak, consider using a leak detection tool. There are several on the market, and all work slightly differently. With Leakbot, for example, you attach it near your stopcock, and it uses technology to monitor the temperature of the water going through your taps.

A leak detection tool triggers an alert if there’s a leak, which gets sent to you on a mobile app, giving you a chance to take a look and see if it’s something you can fix or get in touch with a plumber. The time and money a leak detection tool could potentially save you make it well worth the small initial investment.

Common places for water leaks in the house

If you think you have a leak and don’t have a leak detector that tells you where it might be, there are some common culprits around the home that are worth checking first:

Water tank/boiler

Check the valves that take water into/out of your boiler or water tank. You should quickly be able to see a leak. If there isn’t any water escaping, look for signs of a slow leak, including marks on the floor below the valve or a hissing sound.

If you have a leaking boiler, this isn’t something you can fix yourself, and a leak may be a sign of something seriously wrong, so contact a professional.

Toilets

Because of how much we use them, it isn’t unusual for a toilet to start leaking. This isn’t usually something to worry about, but it can be costly if your toilet is continuously running. You might be able to fix it yourself; changing a washer out is relatively straightforward, for example, and saves you money rather than calling a plumber.

Life hack: If you aren’t sure your toilet is leaking, a trick is to put food colouring in the tank and leave it for 10 minutes. If you go back and the water in the bowl is the same colour as the water in the tank, you’ve got a leak.

Showerheads

Much like toilets, we use showers on a regular, if not daily, basis. This means the parts start to wear down, and you’re likely to find leaks. We’ve already talked about how low pressure could be the sign of a leak (as well as a clogged showerhead), so it makes sense this would be one of the first places to look if you think you have a problem.

Appliances

Through everyday use, appliances can shift slightly from their original position, which can loosen valves and pipes and lead to leaks. Check them regularly to make sure all the attachments are secure.

How to tell if you have a water leak underground

If there are no clear signs of a leak inside your home, your water meter can help you figure out where the problem might be:

• Start by turning off your stopcock, then run a tap to make sure the water is completely off.
• Check your water meter, if the dial is still moving, that means water is leaking somewhere outside, likely along the underground supply line.
• If the meter stays still, the leak is probably inside, possibly in a hidden pipe or appliance.

Once you've ruled out an internal leak and suspect it's underground, the next step is to look for signs around your property.

In some cases, finding the source may mean digging into your lawn or, if the leak is under concrete, spotting it might take a bit more detective work. Watch out for the following indicators of an underground water leak.

Cracked or warped pavement

Sudden cracks or bumps in your driveway or sidewalk can be a sign that water is leaking underground. As the water seeps out, it can wash away the soil beneath, causing the pavement to shift or break.

Wet or damp areas

If you spot random wet patches in your garden or driveway, especially when it hasn’t rained, it could be a sign of a leak underground. Soggy ground or puddles that keep coming back without a clear reason might mean water is escaping below the surface and soaking through.

Foundation cracks or shifts

Noticing new cracks in your home’s foundation or feeling like parts of the floor are shifting? That could be a sign of a hidden water leak underground. When water seeps into the soil below your home, it can cause the ground to move or settle, which puts pressure on the foundation.

Running water sounds

Hearing the sound of water running when no taps or appliances are on can be a clue that there’s a leak underground. It might sound like a trickle, whoosh, or faint humming coming from walls, floors, or pipes.

What to do if you have a leak in your house?

Assess the severity

If you do find a leak, the first thing you need to do is work out if it’s serious. Is it going to get worse quickly and cause significant damage? Alternatively, is it limited to a particular appliance, such as a toilet or washing machine?

If it’s a significant leak or it’s spreading fast, we always recommend contacting a plumber who can safely and properly resolve the problem. Acting quickly can help prevent bigger problems down the line, especially if the leak is hidden or affecting your home's structure.

For smaller leaks

If it’s a small leak that you can fix, you can turn off the water to the appliance while you get the supplies you need to make repairs. If it’s a more significant leak, however, you will need to turn off the water at the stopcock, which will mean no water is going into your house, and the leak shouldn’t get any worse.

Important: You should also turn off the electrics to any part of the house affected by the leak.

Regularly check your stopcock

Stopcocks can sometimes seize up if they haven’t been used in a while, just when you need them most. If you can’t turn off the tap, you can’t stop the leak. To avoid this, make a habit of turning your stopcock on and off every so often to keep it moving freely. A simple check now could save you from major damage later.

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