Home Improvement

Leaking Radiator Pipe: Causes, Symptoms and Solutions

There are few things more annoying than the sound of leaking water in the house. If you have a leaking radiator pipe, one day you’ll get surprised by a puddle on the floor under the radiator. If you have a carpet, it can get seriously stained, because the water is most probably full of rust and other particles. If you have a hardwood floor, it can get damaged if the puddle is left there for a long time. And worst of all, the leak will get in the way of your heating system working properly.

Well, don’t worry! The Fantastic Services team of professional plumbers is here to tell you what causes a radiator pipe to leak and what you can do about it. This article is for all of you who:

  • Have to deal with a leaky radiator pipe;
  • Wish to know how to fix the problem yourselves.

Symptoms of a leaking radiator pipe

Of course, the most obvious symptom is the puddle on the floor. But, there are times when the leak is so small, it takes a long while until you realise there’s a problem. So, if you have a pinhole rupture somewhere on your radiator unit or the pipelines, and water is leaking at a very slow rate, look around for:

  • Mould. Just because the leak is tiny, it doesn’t mean that mould is sleeping. Mould and mildew can grow over the damp areas around your radiator. The blackening of those areas might be what directs your attention to the damage.
  • Damaged walls. If the water is spraying against the wall, there might be some staining and paint chipping. It may take a while until there’s an actual danger for the wall, but it is a warning sign.
  • Sparks from your electrical outlet. This is highly unlikely, but if the leak is positioned too close to an electrical socket and water gets in it, you’ll know immediately.

Causes for a leaking radiator pipe

  • A leaky radiator valve. In the vast majority of cases, the problem is a faulty radiator valve. This happens due to general wear-and-tear. Eventually, the valve will not be watertight anymore and will start leaking.
  • Loose or damaged spindle. The joint that connects the radiator unit to the valve is called a spindle. If it’s leaking, it’s probably because the gland nut is loose.
  • A rusted and corroded radiator. Over time, corrosion occurs inside every radiator. Especially if yours is particularly old. If you don’t use a chemical inhibitor, it will get even worse to the point of causing holes at the bottom of your radiator unit.

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How to fix a leaking radiator pipe

If you notice a leak around your radiator, you should act quickly, because the more you wait, the worse the problem will become. So, here are the most important steps you can take to prevent any further damage.

  1. Dry your radiator. The first thing you should do is take a towel and completely dry off the entire surface. This way, you have a better chance to find the source of the leak.
  2. Find the source of the leak. Take a paper towel and move against each part of the radiator. Once the paper sheet gets wet, you have found the hole. Radiator leaks either come from the body of the heater, the bleed point, the valve, or the pipe that fills the radiator with water.
  3. If the radiator valve is leaking, you’ll have to drain the water to a level below the leak. Use a spanner to undo the union nut and open the bleed valve to allow the rest of the water to leave the radiator. Have a bowl underneath to catch it. Wrap seal tape around the male end of the valve tail. Then, re-tighten the union nut and open the bleed and lockshield valves. Refill the system with water. There shouldn’t be any more leaks. If the problem persists, you might have to replace the radiator valve with a new one.
  4. If the radiator spindle is leaking, then there is damage in the connection between the pipework and the radiator. This one is the most easily remedied issue. Most of the time it can be fixed if you simply use a spanner to tighten the gland nut. If this fails, undo the nut and wrap some sealing tape around the spindle and tighten it again. If this still doesn’t work, then you might have to drain the system and replace the valve.
  5. If your radiator is leaking due to corrosion, then you have let a lot of sludge build up inside your heating system. This is a big problem not only because your heaters are now cold at the bottom, but you’ve literally let your radiators rot from the inside. And if it has come to the point that your radiator itself is leaking, there is no saving it. You’ll need to get a replacement unit.

Do you need professional help with your radiators?

Your heating system is a complicated contraption and a lot of things can go wrong with it, be it due to time, or poor maintenance. If you’re having trouble with a persistent radiator leak, resolving the problem might prove to be difficult without the proper experience. In these cases, don’t hesitate to ask a professional plumber for help. The Fantastic Services team of reliable technicians is always ready to find the source of the issue and fix it promptly. Check our plumbing cost guide to become more familiar with prices for pipe replacement.

Visit the main website for price rates for our professional plumbers!


  • The most obvious symptom of a radiator leak is the sound of dripping water and a puddle below the unit;
  • The most common causes of a leaking radiator are damaged valve, damaged spindle and general corrosion;
  • The valve can be easily fixed with seal tape, or can be replaced if the damage is severe;
  • If the spindle is loose, it just needs to be tightened with a spanner;
  • If you have let your radiator corrode from the inside and it has started leaking, you will have to replace the whole unit.


Have you ever had a leaking radiator pipe? How did you deal with the problem? Tell us in the comment section below!

Image source: Yevhen Prozhyrko/shutterstock.com

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