Hidden water leaks are one of the most frustrating and costly issues UK homeowners face. Because they’re often out of sight — behind walls, under floors, or buried in pipework — you might not notice a leak until serious damage is done.
Here at Heating & Plumbing Doctors, we highlight one of the easiest and most reliable ways to detect a hidden leak before it escalates into a much bigger problem.
Why Hidden Leaks Are So Dangerous
Unlike a dripping tap or a burst pipe, a hidden leak can quietly:
- Increase your water bills
- Damage timber, plasterboard, or flooring
- Lead to mould and damp patches
- Affect boiler pressure and heating performance
The longer they go unnoticed, the more expensive they become to fix.
Expert Tip: Check Your Boiler Pressure
In our video, we explain that one of the most common early signs of a hidden leak is your boiler’s pressure gauge constantly dropping — even after you top it up.
Here’s what to look for:
- You’ve recently topped up your boiler pressure
- But within a few days, the pressure drops again
- There are no visible leaks around radiators, valves or pipework
If this sounds familiar, you may have a hidden leak in your heating system — likely under the floor or in concealed pipework.
The Bucket Test: How to Spot the Issue
The video shows a key diagnostic clue: the presence of water coming from the pressure relief pipe (PRV).
To check this yourself:
- Find the small pipe sticking out outside your property near the boiler
- Place a bucket or container underneath it
- Leave it for a day or two — then check for water
Water in the bucket = your system is losing pressure via the PRV, often due to internal pressure problems or a leak somewhere in the system.
What To Do If You Suspect a Hidden Leak
If your boiler keeps losing pressure and the bucket test confirms water loss:
- Don’t ignore it — your system is under stress
- You may have a leak in a hidden pipe, behind a wall, or under flooring
- It may also be a faulty expansion vessel or PRV valve
Heating & Plumbing Doctors can carry out a full diagnostic, using tools like thermal imaging, pressure testing, and leak detection equipment to locate the issue without tearing up your floors unnecessarily.
Stay Ahead of Hidden Leaks
Regular boiler servicing, checking your pressure gauge, and acting early when you spot signs can save you thousands in water damage or heating system failures.
Got concerns about your boiler pressure or suspect a hidden leak?
Contact Heating & Plumbing Doctors today for expert help and peace of mind.
