Although the work itself may not require planning permission you should clarify ownership and responsibility before modifying or carrying out maintenance.

Drains, sewers and manholes may be shared with neighbours or owned by the relevant water authority.

Failure to confirm these details or to comply with relevant standards/legislation could lead to legal and remedial action at your own cost.

Don't forget to consider utilities when planning your project.

If you wish to repair or replace an existing drainpipe, manhole or associated fitting, approval under the building regulations is not normally required if the replacement is like for like.

However, the provision of a new drainpipe, manhole or associated fitting will normally require approval under the building regulations.

They will apply to new rainwater or foul drains inside as well as outside the building.

The building regulations also apply to all non-mains foul sewerage arrangements (i.e. those using septic tanks), including their outlets and drainage fields.