Gas Boiler Leaking Water

Man connects the gas boiler


Discovering your gas boiler leaking water is enough to make your heart sink – even if it’s still working, a gas boiler leaking water may well not be working for much longer.

A gas boiler leaking water isn’t necessarily a sign of a potentially dangerous problem, but it certainly isn’t a problem you should attempt to fix yourself. Like any other gas boiler repair, it should be looked at by a professional. For good reason, it is illegal for any company to carry out gas boiler servicing and repairs without being RGII registered. If you notice your gas boiler leaking water, switch the boiler off and call Gas Services straight away. Our fully trained, qualified and registered gas installers boast a first time fix rate of 80%, meaning we’ll have you back up and running in no time.

But why is your gas boiler leaking water? This depends on where the leak is coming from, and it could be any one of the following problems:


Corrosion is one of the most common causes for a gas boiler leaking water. Over time, the various components within a gas boiler can begin to corrode and weaken, allowing water to escape. Individual valves and other components can be replaced, but if the corrosion is more widespread it may be more economically viable to replace the whole gas boiler. If we find this is the case, we will carry out an immediate on­site assessment and quickly provide you with a no­ obligation quote for a best­ match replacement. We will always try to save you money where we can by working with your original pipework wherever possible.

High Pressure

If the water pressure in your boiler is too high, the pressure valve is designed to leak in order to prevent dangerous explosions. However, despite this, you should always keep an eye on the pressure gauge. Limescale can clog up the pressure valve over time, preventing it from releasing water safely.

Pump Seals

It is common for the seal of the boiler pump to become corroded and to leak. If this happens, you may need to have the pump re­sealed or replaced.

Pipe Fittings

If your boiler has been installed incorrectly or badly, you may find that the pipe fittings will leak, causing the water pressure to drop.

High Temperature

Similarly to the pressure valve, if the boiler temperature becomes too high this can cause the temperature valve to leak. This can be due to a fault in the boiler, and should definitely be investigated as soon as possible.

Although these are common causes for a gas boiler leaking water, there could be many other explanations. In any case, a gas boiler leaking water should be investigated as soon as possible to prevent further damage or breakdown. A water leak will cause the water pressure to drop, stopping the boiler from functioning properly.