Do you need a drain test for building control?
The Building Control officer for your local London Borough require that all newly laid drainage is successfully tested for water-tightness, as per the relevant British Standards (BS EN 752:2008).
Who would need a drain test?
Building contractors and house builders are normally the people who ask about drain testing. Quite often they are unaware a drain test is necessary until they speak to Building Control. Then they are in an almighty rush for a test to be done, so that they get the build signed off.
What are the different types of drain test?
There are two different drain tests; the Air Test and the Water Test. Usually, an air test is carried out to all new pipework and drainage following installation, while a water test will only normally be required to verify a failed air test or to test manholes or inspection chambers are watertight.
How we do the air test?
We block both ends of the pipe or drain. We would then use air to pressurise the pipework. We then use a pressure guage to monitor the pressure for five minutes. A drop in pressure would mean a failed test. We would then look for any leaks, repair as required and re-test as needed.
Who needs to be present for a drain test?
A drain test is normally carried out in the presence of a Building Control Officer, although the contractor will sometimes ask us to do a preliminary drain test to ensure the drainage will pass.
Some local authorities in London will permit our engineers to self-certify your drainage without a Building Control officer being present as they are have passed the necessary qualifications.
What needs to be done before doing a drain test?
Before carrying out a drain test, pipework should be visually inspected for any obvious signs of damage or leaks. Mortar-jointed systems should be left for at least 48 hours before a drain test.
What if the drain test fails?
A failed air test is not the end of the world. It just indicates a leak somewhere in the system. In the first instance, the engineer will check all the pipe connections are correct. Our engineers are there to try and help and will do what they can, to make sure your drain test is successful.
How much will a drain test cost?
It really depends on the layout of the drains. Sometimes a small extension will take longer than a new build, depending on how the pipework is configured and what the engineer finds. We find the simplest way is to quote an hourly rate. That way if it only takes an hour, that is all you pay.
Do homebuyers need to have the drains tested?
A drain test is only normally done when you need to prove something is watertight after building work. We don't normally carry these out for a pre-purchase survey. What we recommend is a pre-purchase cctv drain survey. This would show any problems within the drainage system.