Radiator leaking water from bottom? Three DIY answers to fix
Is there water seeping out from underneath your radiator? Either a quick do-it-yourself fix or a new radiator could be in order. We examine how to prevent it from leaking.
Although a radiator leaking water from the bottom is a common issue, competent do-it-yourselfers can usually quickly and easily resolve it. If the problem can be solved by just tightening a nut, you may be extremely fortunate.
Even though most of us want the simplest solutions, you’ll probably need to put in a little extra effort. Finding the leak should be your first goal. Which direction is it coming from the radiator, the nut, or the valve itself? Once located, it can be resolved.
To restore your radiator to full functioning order after you’ve repaired the leak and replaced the radiator, you’ll need to learn how to bleed a radiator.
How to stop radiator leaking water from bottom
Usually, a leaking valve is the source of the issue when your radiator leaks from the bottom and leaves puddles on the floor. This is how to arrange it.
- Fasten the bolt Firmly
A nut commonly referred to as a union nut holds radiator valves to radiators. The problem might be resolved with a straightforward nut tightening. This is your first option, and hopefully it will work. If not, we move on to the following fix. - Replace the Valve
Refitting the valve is the next step. It might only be necessary to add or replace PTFE tape around the thread if the leak is coming from the union nut and the valve. Prior to doing this, though, you must learn how to isolate a radiator, which entails shutting the radiator’s valves to halt the water flow and allow it to drain. After isolating the valve, remove the union nut, empty the radiator, and dry the valve’s threads. Proceed to wrap the thread with PTFE tape and tighten the union nut. - Change the Valve
Remove the old radiator valves and install new ones if the leak is coming from the radiator valve itself rather than the joint. You must ascertain the size of your pipes; depending on the type of system you have, they are usually 15 mm or 10 mm in diameter. For additional assistance with this, be sure to read our guide on fixing a leaky radiator.
What do I need to do if it’s not the radiator valve?
There might be a leak in the radiator itself if the radiator valve is not the issue. There might be a rust spot on your old radiator that has finally cracked. In an attempt to cover up rust spots, painted radiators frequently have these. Look for areas that have risen to the surface, and check to see if they are wet by placing a dry finger there.
As an alternative, look up vertically and observe where the water is pooling. Leaks near the vertical line will indicate that the radiator is the problem. Keep in mind that it could be hidden behind or inside the radiator, making it more difficult to find. It’s time to replace the radiator if it turns out to be leaking.
Will turning off a radiator stop it leaking?
When a radiator is turned off, water stops entering the radiator through the pipes. Since there will still be water in the radiator and the valves, this is unlikely to stop any leaks, but it will slow the leak down because there won’t be any water going through.
On the other hand, you can undo the valves and drain the radiator after you have isolated it. Make sure you have enough towels and containers ready to absorb the excess water. Two to three litres of water should be released by a single panel radiator of average size. Naturally, a double-panel radiator will release more, so be ready.
It goes without saying that an empty radiator will stop any leaks, and if the leak was caused by the union nut, this will also stop it. But if the valve is the issue, the leak might not stop. To help absorb leaks, get a towel and wrap it around the radiator valve.
One possible cause of your radiators not heating up to their full potential could be a leak. However, like many plumbing issues, it’s not always that easy. For assistance with any heating or radiator problems, see our quick fix guide on radiator not heating up.






