August 22, 2023


Boiler Leaking Water – Causes and Fixes

Once your boiler begins to leak, you are in a challenging situation as it may lead to hefty damages to the boiler and your home. Knowing the reason behind the leaking boiler can help you fix it if it is fixable. But in most cases, it’s best to look for a professional engineer. Their expertise and tools are necessary for repairing or replacing your leaking boiler.

Let’s discuss the causes of leaking boilers and how to fix them.

Why is My Boiler Leaking Water?

There can be several potential causes for boiler leaks, and knowing the exact cause of water leaks can help determine the right solution. Here are seven common reasons our engineers have found behind boilers leak and how to fix these.

7 Common Causes of Leaking Boiler

Heat Exchanger Corrosion

Corrosion can cause rust and debris to the exchanger system, which is the device that heats the water. In this case, you’ll need to consult a qualified boiler installer to open up the boiler to find the corrosion and repair/replace it.

Boiler Auto-Air vent

A boiler that leaks from the top might have a problem with its Auto-Air vent. When the pressure gets high, the Auto-Air vent automatically releases the pressure. It is possible due to a valve that opens and closes. So, at times the valve may stick. This situation makes the Auto-Air vent release both water and air.

Pressure Release Valve

In case of a leaking boiler, most likely, your pressure release valve is not working. Boilers come equipped with highly effective pressure-release pipes. These pipes are not sealed to allow excess pressure to escape. Thus, if the leakage is tiny, then the problem is minor. If you see dripping water, the boiler’s pressure is much too high. A boiler professional would need to repair it and lower the pressure.


A valve is installed to control the temperature of a boiler. So, if you find a leak coming from the temperature valve, that might suggest that the temperature is too high.

Boiler Heating Pump Leaks

A boiler pump pumps water to the rest of the heating system. So, if you see any leaking in the pump, there is a problem with the boiler’s pump seal, or something is wrong with the pump itself. A boiler expert can fix the boiler or replace it with a new one.

Boiler Connections

Joints are prone to tear and wear over time due to the expansion and contraction of the vessels, which is why leaking joints is so common. It is because of the changes in the water’s temperature.

Poor installation

Poorly installed connections or the wrong components can lead to boiler leaks. Overall, having a certified professional fix your boiler system is the best approach to avoid or fix this.

How to Fix a Boiler Leaking Water?

  • Dry off the one that you suspect is leaking. Wait and see if the water reappears.
  • If you see the leak, you can tighten the fittings with a spanner until the water stops dripping. On the contrary, corrosion may have gotten the better of the seals.
  • You must talk to a Gas Safe registered professional to resolve the boiler leak problem.

You can try finding the cause of the leak and fixing it on your own. However, this can be time-consuming and unsafe. So, it’s always better to get a professional to do it.

Get Repairs Done Quickly with Professionals

Always consider getting repairs and replacements by reliable certified installers like the TBIS. Our engineers can identify all types of boilers leaking problems, whether it leaks from the top or the bottom. We are certified partners of popular boiler brands like Worcester Bosh and Valliant. You don’t only get well-trained and knowledgeable boiler installers but also boiler finance options to get a new boiler easily.

Some common questions related to leaking boiler:

  • Can I use my boiler if it is leaking?

If you have a leaking boiler, you should shut it off immediately.

  • What should I do if my boiler is leaking?

Turn off the water supply and call an engineer straight away.

  • Does a leaking boiler cause low pressure?

Yes, a leak in any part of your heating system will cause a drop in pressure.

  • How dangerous is a leaking boiler?

A leaking boiler leads to many more mishaps, including a short circuit due to water dripping on the electrical parts. If the leak persists, it could harm your walls, flooring, and belongings.

  • How to prevent a boiler leakage?

Schedule an appointment with a registered engineer to detect potential problems. They can take preventative measures like running a chemical flush through your system to rid it of dirt and debris. Also, install a magnetic filter to remove the debris before it accumulates.

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