Do I Have a Water Leak? 10 Signs to Check For

By HUBB Group  ·  Updated August 2026  ·  6 min read

A hidden water leak rarely announces itself. Most people don't find one because of a dramatic burst pipe - they find it because a water bill looks wrong, a room smells musty, or a patch of ceiling won't quite dry out. If you're wondering whether what you're seeing is actually a leak, here's how to check, what to look for, and what to do next.

The quickest way to check: a water meter test

If you have a water meter, this takes about an hour and costs nothing:

1. Make sure no taps, appliances or outdoor hoses are running anywhere in the property.
2. Note the exact reading on your water meter.
3. Don't use any water for 1-2 hours - the longer you can leave it, the more reliable the result.
4. Check the meter again. If the reading has moved and nothing has used water in that time, there's a leak somewhere in the system.

This test confirms that you have a leak, but not where it is - for that, the signs below and a professional investigation are the next step.

10 signs of a hidden water leak

• An unexplained rise in your water bill - the most common first clue, especially if your usage habits haven't changed.
• The sound of running water when everything is switched off - a hiss or trickle behind a wall or under a floor.
• Damp patches or a persistent musty smell - particularly on walls, ceilings or in cupboards that back onto plumbing.
• Mould growth that keeps returning even after cleaning, especially in one consistent spot.
• A warm patch on the floor - usually a sign of a leak in an underfloor heating pipe or hot water supply.
• Flooring that's lifting, cracking or discolouring without an obvious cause.
• A noticeable drop in water pressure from taps or the shower.
• Damp patches or pooling water outside, particularly near an external wall, even in dry weather.
• A boiler or heating system that keeps losing pressure and needs regular topping up.
• Cracks appearing in walls or foundations - a later-stage sign, as sustained water ingress can affect the structure itself.

One or two of these on their own aren't necessarily a leak. Several together, or any of them alongside a meter test that confirms ongoing water usage, are worth taking seriously.

What to do if you suspect a leak

If the leak looks serious - visible water, a rapidly rising bill, or a boiler that won't hold pressure - turn off your stopcock (usually under the kitchen sink or where the supply enters the property) to limit further damage, then arrange an investigation.

What we'd steer you away from: lifting floorboards, breaking into a wall, or digging up a driveway to "have a look." Without knowing exactly where the leak is, this kind of exploratory work often causes more damage than the leak itself - and if you're planning to claim on insurance, unauthorised repair work can complicate that too.

How professionals find leaks without damage

HUBB Group's engineers use three non-destructive methods to confirm a leak's exact location before any repair work begins:

• Thermal imaging - infrared cameras detect the temperature differences caused by water behind walls, under floors and inside pipework.
• Acoustic detection - ground microphones and pipe-correlation devices listen for the unique sound signature of escaping water.
• Tracer gas - a safe hydrogen/nitrogen mix traced to the leak point with sensitive detectors, the gold-standard for slow or intermittent leaks.

Combining these means the exact source can usually be confirmed in a single visit, with a written report suitable for your insurer - without lifting a floor or breaking a wall on a hunch.

Frequently asked questions

How quickly can a leak be traced?

Most investigations are completed in a single visit. We guarantee a 4-hour response for emergencies across Essex and the wider Southeast, with most jobs reached within 60-90 minutes.

Will finding the leak mean lifting my floors or breaking walls?

Almost never. We use non-destructive methods - thermal imaging, acoustic listening and tracer gas - to confirm the exact location before any repair work begins, so any access needed is minimal and targeted.

What if I can't find any obvious sign of a leak but my water bill has still gone up?

This is common with underground or under-slab leaks, which rarely produce a visible damp patch. A water meter test is the best first check, followed by a professional investigation if the meter confirms ongoing usage.