Published: Thursday 26th June, 2025

5 Signs That You May Have a Water Leak

Not all leaks are obvious. Some are slow, hidden, and quietly causing damage behind the scenes — and if left undetected, they can lead to costly repairs and rising water bills.

If you’ve noticed a drop in water pressure, unexpected damp patches, or a spike in your usage, there’s a chance you’ve got a leak somewhere in your plumbing system. Here are five of the most common signs to watch out for.

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1. Your water pressure has suddenly dropped

A noticeable dip in pressure — especially if it’s only affecting one part of your home — could mean water is escaping somewhere along the line before it reaches your taps. If there’s no obvious fault with your boiler or fittings, a hidden leak could be the cause.

If you haven’t already, check out our guide about water pressure: Why is my water pressure so low? 9 common causes and fixes. 

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2. Your water bill has gone up — or your meter is still running

Most households use roughly the same amount of water each month. If your bill has crept up unexpectedly — and you haven’t had guests staying or started using more water — it could be a sign of a continuous leak.

Homes with a water meter can run a simple check: turn off all taps and water-using appliances, then see if the meter is still moving. If it is, water is likely escaping somewhere in the system.

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3. You’ve noticed damp patches or mould

Leaks that go unnoticed can lead to moisture build-up around walls, ceilings or floors. Look out for discoloured patches, soft or spongy surfaces, musty smells, or spots of mould — especially near bathrooms, kitchens, or pipework runs.

These signs can be easy to miss at first, but they’re often the earliest clue that something’s wrong.

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4. You can hear dripping or hissing sounds

Sometimes, the first sign of a leak is a sound — not a sight. If you can hear dripping, hissing or the sound of water running when everything's turned off, it could point to a hidden pipe leak behind walls or under floors.

It might not be loud, but it’s worth investigating, especially if the sound is consistent or you can’t locate the source.

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5. There’s a sagging ceiling or bulge in the plasterwork

If a leak is coming from above — whether from a bathroom, pipe joint, or tank in the loft — you might notice a visible sag in the ceiling below. In some cases, the plaster may feel soft or look slightly bowed. Over time, the ceiling may begin to stain, bubble, or even crack.

This is a clear sign that water is pooling somewhere above and needs to be dealt with quickly to prevent further structural damage.

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What to do next

If you’ve noticed one or more of these signs, it’s worth getting a professional to carry out leak detection. The sooner a leak is found, the less chance there is of long-term damage.

Some leaks are small and easily fixed — others can lead to serious structural issues if left alone. If in doubt, get it checked.

You can also protect your home against future leaks with our Home and Complete cover plans — they include unlimited repairs and support when you need it most.  View our plans here.