How to Fix a Radiator Leak

Written by
Giulia C
Published on
November 24, 2025
Introduction
If your radiator leaks water, that is a problem. The leak can get bigger. Make a puddle or drops of water can come out from under the valve. If you do not fix the leak in your radiator, it will hurt your floor. Cause trouble with your heating system.
The good news is that a leak in your radiator can be fixed. It is not hard to fix a radiator leak, especially if it just started leaking.
Before you start fixing the leak, you need to make sure the leak is actually coming from the radiator and not from a pipe or valve that's closed. The radiator leak usually has some signs.
* Water has collected at the bottom of the radiator
* You can hear a drip coming from the valve or the screw that you use to bleed the radiator
* There are damp or rust marks on the radiator
* The radiator is not heating well as it used to the heating output of the radiator has been reduced
Leaking radiators can be caused by several things. Here are some reasons:
* Loose valves or ones that are worn out can cause leaks.
* The radiator's body or seams can get corroded, leading to leaks.
* The PTFE tape or sealant on joints can get old and damaged, causing leaks.
* The bleed valve can also leak.
* Rust and sludge buildup can cause cracks or pinholes in the radiator, leading to leaks.
Before you start:
* Switch off your boiler. Let it cool down
* Close the radiator valve and lockshield valve on the leaking radiator
* Put towels or a bucket under the leak to catch the water.
A dry cloth will be used to wipe the radiator. This will help find where the leak is coming from.
Is water leaking from the valve?
Is the leak at the screw?
Is the radiator body rusty or cracked?
Check the joints and seams for signs of corrosion.
Once we find where the leak is, we will fix it. The right fix will be used.
We will use the method to stop the leak once the source is identified.
Published: November 25, 2025
Updated: June 25, 2026
