Planning permission is required to replace or fit a foul sewer system, including packaged treatment plants, septic tanks or tight tanks.
You do not need planning permission to maintain or repair to an existing system, for bore holes or other minor below ground drains.
However planning permission is required if your property is registered as a listed building or place (LBP) or a potential listed building or place (pLBP).
Building permission is required if you wish to provide or alter a drainage system.
The building bye-laws apply to rainwater and foul drainage systems inside and outside the building.
It is good practice to get the drainage tested before any backfilling. The Building Control section of the the Environment Department will ask to witness a test on completion of the work.
Making an application - building