Put a nail through a water pipe? This is what to do

Those who regularly read the CIPHE blog will know that we advise against DIY on plumbing and heating systems. However, with water pipes running throughout your home - hidden from sight behind floorboards and walls - the likelihood of damaging a pipe while doing other jobs is higher than you think.

So, what do you do if a rogue nail hits a water pipe? The CIPHE has the following advice should the worst happen over this bank holiday weekend.

1. If possible, position a bowl or bucket in place to catch any flowing water and then try to isolate the leak.
2. Turn off the mains stop valve (often referred to as stopcock), this should stop the flow of water. Then call a plumber. Make sure you know where your stop valve is (often under the kitchen sink) and test it regularly to ensure you can turn the valve on and off freely.
3. Open other water outlets lower than the leak to help to drain the pipework faster.
4. If the leak is on a hot water pipe, regardless of system type, isolate the power to any central heating boiler or immersion heater.
5. If the leak is on a central heating pipe, then turn off the boiler/heat source immediately. If you have a combination boiler the leak will eventually cause the pressure to drop, and the flow of water will reduce and stop. Do not attempt to re pressurise the system until the leak has been fixed. For older systems, stopping the flow of water to the leak will not be as straightforward as it will require isolation of the water to the tank/cistern in the roof space.
6. In all instances, once the flow of water from the pipe can be controlled/stopped or at least captured to prevent damage, you will need to contact a professional plumber/heating engineer.

You must be aware that if you caused the leak, you might not be covered by your house insurance. Firstly, you need to make sure you have accidental damage covered on your policy, secondly you need to read the small print; if you have attempted work that you are not competent to do, you may find your insurer won’t pay out.

To find a plumbing or heating professional please visit our Find a Plumber page.