Access is required to drainage installations for testing, inspection and removal of debris. Access to drainage allowing rodding in both directions can be provided by inspection chambers. Rodding eyes provide access for clearance of debris in the direction of flow only and should only be used in conjunction with an access chamber or manhole at a point downstream.

No part of the drain should be more than 50 metres away from a manhole. The distance between points should therefore not exceed 100 metres.

Generally speaking, access should be provided at all changes in direction, gradient or pipe size, unless rods can pass through unimpeded.

Where a junction between two drains does not have a manhole, access should be provided within 12 metres of a junction.

British Standard access spacing requirements

Access fitting 1Access fitting 2To Branch or JunctionShallow Inspection ChamberManhole or Deep Inspection Chamber
Start of external drain* 12 12 - 22 45
Rodding eye 22 22 22 45 45
Type 1 access fitting - 150 x 100mm - - 12 22 22
Type 2 access fitting - 225 x 100mm - - 22 45 45
Shallow inspection chamber 22 45 22 45 45
Manhole or deep inspection chamber - - - 45 90

* Stack or ground floor appliance.