A leaking water boiler by itself might not seem like a big deal, but it’s essentially a catalyst for much bigger problems if not dealt with in a timely manner. What could be a simple fix can turn into a more expensive one, or even a full replacement if the damage has gone too far.

But luckily, most of the times when identified early on, it is just a simple fix.

Therefore, the first step to take when you see a water boiler leaking is to identify the cause. This will determine how serious the problem really is and determine what will be the next step. 

“Start by doing what's necessary; then do what's possible; and suddenly you are doing the impossible. – Francis of Assisi

How bad is it?

First of all, let’s assess the situation: in most cases, the water boiler leaking isn’t a big deal – at least, not immediately. If you notice water leaking, try to get it fixed quickly because water damage is a possibility. As long as you’re efficient in dealing with the problem, you have nothing to worry about.

Gas leaks however are a bigger concern. If you smell gas leaking from your boiler, switch off the gas supply immediately, ventilate the area, and vacate the premises. Call the National Gas Emergency line for instructions at 0800 111 999 or call a professional.

Now, let’s take a look at some of the most common reasons why your water boiler is leaking:

1. The pressure is too high

If the pressure is too high, this may lead to a leaking pressure valve. Fairly easy to fix, but with a high enough pressure it can rupture the boiler, so it must be dealt with as early as possible.

You can try to decrease the pressure by loosening the nut on the end of your radiator to release some water. Let some water out and tighten the nut again. You can try this process a few times to see if it helps with the pressure.

2. The temperature valve is leaking

The main reason why a leak would come from the temperature valve is if the appliance temperature is too high. Check the temperature probe inside your boiler as it may need replacing!

Here – and for any of the following reasons – always call a professional if you’re unsure or insecure on how to approach your boiler. Some repairs can be dangerous, so it’s always better to call a pro and stay safe.

3. Boiler pipes are leaking water

There are two possible explanations: either your pipes have suffered some sort of damage or degradation and need to be checked, or most likely, if the installation is somewhat new, it’s quite common for leaks to occur – as they are hard to spot early on.

Simply hire a pro or call the one who made the installation and they will know what to do!

4. Leaking from the bottom

This is one of the worst leaks you can have when it comes to your boiler, but it tends to happen in old types, not so much on new ones. This means the pipes inside the boiler may be compromised and need to be inspected – and likely replaced – immediately.

Corrosion may be the culprit, and if it has spread to the rest of your boiler, it might need to be replaced as well. But if identified early, just replacing the pipes is enough.

As a temporary “band-aid while you wait for a professional, place a recipient under the boiler to take in the water and if possible tie a piece of cloth around the leaking area just to slow down the leak until you can fix it.

5. The overflow pipe is leaking

The overflow pipe stays outside your property and can leak as well. Usually this is a problem with your float valve – this is the mechanism that controls the water level inside the tank. If it’s not working, the excess water will leak through the overflow pipe.

Usually replacing the float valve fixes the issue entirely!

6. You smell a gas leak

Probably goes without saying, but this is possibly the most dangerous leak on the list: a gas leak is a serious fire hazard and health risk. 

The second you smell gas, turn off your gas supply, ventilate the area by opening doors and windows, and leave the house. Then call the National Gas Emergency line or your professional of choice for boiler repairs. 

If you can’t smell it, do keep an eye out for scorching or soot marks on your boiler, unusual condensation on your windows, and a different-colored pilot light on your boiler (yellow or orange). If you notice these signs, take the same precautions listed above.

Need help with a water boiler repair? Get free quotes from professionals in your area today!


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