Do I need permission to install WC, shower, washbasin, kitchen sink or similar?
If the installation will involve alterations, or new connections to, a drainage stack or an underground drain, you will need permission. You should also check to find out how much information is required about the fittings you intend to use.
If you are only installing an additional fitting or fittings in the same or a new location which does not involve extensions to the drainage pipework you will not need permission.