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How to determine if you likely have a hidden water leak
A hidden water leak can cause serious damage to your home if left undetected. From rising water bills to structural damage and mould growth, domestic water leaks often start small but quickly escalate into costly problems. Understanding the early warning signs of a water leak can help you take action before major damage occurs. If you suspect a leak anywhere in your home, our specialist leak detection services at Leapfrog can accurately locate the source without unnecessary disruption. We also offer trace and access services to ensure a thorough water leak detection, helping you safeguard your property.
Damp
High water bill
Unexplained damp areas on walls, ceilings, or floors are strong signs of a water leak. These patches may appear darker than surrounding areas and often grow over time.
Common locations include ceilings below bathrooms, walls near plumbing fixtures, floors near kitchens or laundry rooms
High water bill
High water bill
One of the most common indicators of a hidden water leak is a sudden increase in your water bill. If your usage hasn’t changed but your bill has gone up, water may be escaping from a pipe behind walls, under floors, or underground.
Tip: Turn off all taps and appliances and check your water meter reading. Wait 30 minutes, if the metre reading continues to move, you likely have a leak. If the meter reading remains the same you are unlikely to have a leak.
Mould or Mildew growth
Persistent moisture from a leaking pipe creates the perfect environment for mould and mildew. If you notice a musty smell or visible mould forming in areas that should be dry, there may be a hidden leak nearby. Mold on ceilings and walls can be caused by poor ventilation but could also be a key indicator of a hidden water leak.
Mould not only damages your home but can also affect indoor air quality and health.
Boiler pressure loss
Boiler pressure loss
A gradual and reoccurring loss of system pressure in your boiler is a good indicator that there is a heating system leak.
Plumber advice
Boiler pressure loss
Pooling of water
Often your first point of call may be a local plumber. Whilst plumbers and heating engineers can be a great resource to pull on they may not be able to find a hidden leak and may refer you to a specialist leak detection company.
Pooling of water
Boiler pressure loss
Pooling of water
Leaks don’t always occur inside the home. If you notice soggy patches, pooling water in your driveway or garden, or unusually green grass in your garden, or near your property during dry weather, you may have an underground water leak.
How to Detect a Heating System Leak at Home
A leaking heating system can cause serious problems in your home — from higher energy bills to property damage. At Leapfrog Leak Detection, we specialise in professional leak detection and are at hand to help, but there are simple checks you can do yourself first.
The below guide will walk you through how to detect one of the most common leaks, a heating system leak in a residential property and what to do if you find one.
Why heating system leaks matter
- Increased costs – A hidden leak means your boiler and radiators work harder, driving up your energy bills.
- Property damage – Water escaping behind walls, under floors, or into ceilings can cause damp, mould, or structural issues.
- System breakdown – Left unchecked, leaks can reduce pressure and eventually damage your heating system.
Step 1: Look for Obvious Signs of a Leak
You don’t need plumbing skills to check for the basics:
- Damp patches or water stains on walls, ceilings, or floors.
- Bubbling or peeling paint near radiators or pipes.
- Dripping or pooling water under your boiler or radiators.
- Rust marks around pipe joints or radiator valves.
If you notice any of the above, there’s a good chance water is escaping
Step 2: Check Your Boiler Pressure
Most modern boilers have a pressure gauge.
- A healthy central heating system usually sits between 1.0 and 2.0 bar (check your manual for exact levels).
- If you boiler pressure is dropping you may have a leak. If the pressure keeps dropping even after topping it up, it often indicates a hidden leak in the system.
Step 3: Listen for Clues
Unusual sounds can sometimes point to a leak:
- Hissing or dripping noises near radiators or pipes.
- Air sounds in radiators when bleeding them, which may indicate water loss elsewhere.
Step 4: Feel for Cold Spots on Radiators
Run your heating and check each radiator:
- If one radiator has cold spots at the bottom, it could be due to trapped sludge, but combined with other signs it might indicate water escaping.
- Uneven heating across your home can also be a leak symptom.
What to Do If You Suspect a Leak
- Turn off your water supply if the leak is visible and severe.
- Avoid DIY repairs unless you’re confident – quick fixes can make things worse.
- Call professional leak detection experts like Leapfrog Leak Detection. We use non-invasive methods such as thermal imaging and acoustic technology to locate hidden leaks quickly without tearing up your property.
Why choose Leapfrog Pro leak detection
- Non-invasive techniques – no unnecessary damage to your home.
- Coverage in London and surrounding counties – trusted leak detection services across London, Bedfordshire, Buckenhamshire, Hertfordshire, Surrey, Kent, Suffolk, Cambridge and Essex.
- Fast response times – minimising disruption and property damage.
- Expert advice & repair recommendations/options once the leak is found.
