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You might be asking yourself “why is my boiler leaking?” Having trodden in a puddle of water in your home that isn’t meant to be there!

There are many different happenings that might mean your boiler is leaking water. For many people, the ins-and-outs of boiler systems are a complete mystery, so when it suddenly starts behaving in a way that it shouldn’t, we are left in a state of confusion.

Photo by Luis Quintero from Pexels

This guide intends to explain the factors that cause water to spill out from your previously trusty and dependable boiler, and help you to understand what the issue might be.

Should I try to fix it myself?

As a precaution it should be stated that, if your boiler has begun to leak water, this is a matter of urgency and one that will require the attention of a trained heating engineer. You should not try and attempt to fix the problem yourself, but you should try to decipher what the problem could be.

DIY injuries have seen a sharp increase in recent months as people seek to sort things out for themselves, but boilers are absolutely not to be fiddled with if you have no trained knowledge of them.

Water damage is not a problem that you can simply mop up and ignore, as the leakage is likely to worsen and the water damage can spread to the electrical systems within your house. So even if the problem seems to happen once and disappear, you should still employ the help of a professional.

What immediate steps can I take?

  1. Stem the flow of water with a towel.

This is particularly important if there is a floor situated below the boiler as you want to prevent it seeping through the ceiling.

  1. Steer clear of the electrics whilst your boiler is leaking.

You don’t want to get an electric shock. You should isolate your water supply to the boiler and switch off the electrics to the boiler, or the electrics in close vicinity to the boiler.

  1. Seek out some qualified assistance from a trained professional.

Even if this is the first time your boiler has released any water, you should still treat it as important. Water accelerates the rusting of your pipes, so it is better to stop the source whilst it might be just spitting and not yet a deluge.

7 Common causes of boiler leaks

There are many different reasons that could be the cause of your leaky boiler. Here are the 7 main causes behind boiler leakage.

  1. Pressure Valve Leak

One of the most common causes of boiler leakage is the boiler pressure being too high.

This high pressure means that water must be released from the boiler in order to alleviate the pressure and prevent the boiler unit from breaking. Therefore, if water is leaking from the pressure valve fault this is a safety precaution.

Preventing a leakage due to high pressure can be avoided by checking the pressure gauge needle to see if the pressure is too high.

  1. Temperature Valve Leak

Similarly to a leak from the pressure valve, water might be escaping the boiler through the temperature valve.

The purpose of the temperature valve is to monitor the temperature level in the boiler. Therefore, a leak from the temperature valve could indicate that the boiler’s temperature is too hot.

Extra care should be taken in this situation, as the excess could be scalding hot water.

  1. Corrosion

The gradual corrosion of water pipes, or the actual water tank itself, is a frequent cause of a leaking boiler.

Corrosion can be particularly prevalent in older boiler systems where the pipes have worn down over time. The issue with corrosion is that it has the capability to spread through the system and potentially render the system irreparable, meaning a new one needs to be fitted.

This means detecting corrosion in your system at an early stage is crucial. If the corrosion causing the leak is localised to a single pipe or valve then the job of fixing the leak is much easier.  

  1. Pump Seals

The whole operation of a boiler relies on the system being properly sealed, usually by using rubber sealing on the boiler pump. Over time though this rubber can begin to deteriorate.

This most frequently occurs in older units, but can occur in newer systems if operating at a pressure level that is too high. If water has begun to seep through in this area then a fresh rubber seal will likely be necessary.

  1. Poor installation

Whilst loose joints is not necessarily a sign that the boiler was poorly fitted, water coming from the pipes can simply be the result of a shoddily installed boiler system. The vast majority of boilers are fitted extremely carefully and without cutting corners, however there will always be some boilers that haven’t been properly fitted.

If you believe that your boiler installation was a botched job then you can claim there was a breach of contract. If you don’t believe your boiler was installed properly then Which can show what steps you should take next.

  1. Loose Joints

General wear and tear of boiler systems over a long period of time can also mean that the joints connecting the water pipes can loosen.

The loosening is caused by hot water flowing through the pipes, causing them to expand, followed by cold water, which causes them to contract.  Repeated for years on end, this loosens the piping in its fittings.

To ensure that leaks from loose pipes are not an issue, the pipes and fittings will simply need to be retightened to ensure the integrity of the system.

  1. Old Age

Sometimes a boiler is simply too old to be able to function.

Through years of usage, a combination of some of the above factors can occur due to regular wear and tear in any boiler, rendering it no longer fit for purpose.

When boilers get to this end-of-life stage, it may make more financial sense to invest in a new boiler rather than continually pay for repairs of the old one.  What’s more, you can’t put a price on your peace of mind when boiler leaks are behind you!

If you do decide to replace your boiler, why not fill in the form at the top of this page and let us help you find your perfect boiler and boiler engineer?

Photo by Scott Webb from Pexels

Warning signs that your boiler is not healthy

Sometimes, boilers can give you clues that something is not quite right, even before they start expelling water.  Therefore it can be a good idea to check for the following warning signs:

1. Boiler pressure is too high 

2. Boiler Pressure is too low

3. Boiler is making strange noises and what the noises mean

4. Boiler smells strange. What could it be?

Why is a leaking boiler dangerous?

You should certainly see a leaking boiler as a serious problem and one that can very easily become a dangerous one if you don’t act quickly.

  • Leaking water can cause the electrical components to short-circuit.
  • If not mended, the leak can cause further damage by rusting and corroding the pipes.
  • If left untreated, severe water damage can harm your health by affecting the air quality of your home. It can also lead to the growth of mould, which can spread very quickly in damp conditions.
  • Water leakage can also lead to significant structural damage of your property.

More information on the potential dangers of boiler leaks can be found on Dynamic Heating Services Ltd.

How can you fix your boiler?

The answer is that *you* shouldn’t. Attempting to fix a boiler can be very dangerous, and damaging the unit even further can have even worse consequences. You should call up a qualified professional engineer to stop the leak.

When it comes to having a new boiler installed then HomeSage can help you find the right kind of system for your house and the right person to install it. Simply fill in the form on HomeSage and we’ll help make your life easier when it comes to selecting the right person for the job.

How do I know if I need a new boiler?

In most cases a full boiler replacement is not required if your boiler has started to leak, especially if the problem is one that is relatively easy to rectify, such as a loose joint or a corroded pipe. In this case, requiring a brand new boiler is unlikely to be necessary.

However when problems persist and your boiler continuously leaks then a new boiler will likely be required. This is particularly true of ancient boiler units.

If you are unsure whether you need a new boiler or not, then these 5 signs from Which should help you realise that your boiler cannot be salvaged.      

How can HomeSage help you find the right boiler?

To help you in your quest to find a new boiler that doesn’t turn your floor into a paddling pool, HomeSage can provide a detailed comparison of boiler quotes from leading local and national installers. We will help you find the right boiler for your home, for the right price!


Patrick is a content author at HomeSage. After leaving Leeds University in 2019, he discovered a passion for writing. His main hobbies include football, cricket, quizzing and, of course, boilers!