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PolyDrainage Help & Guides


Inspection Chambers

What is an Inspection Chamber & Base?

Inspection Chambers are access point which allows inspection to the chamber base which connects the underground drainage pipes.

These are necessary in case a drainage pipe needs to be inspected, unblocked, surveyed, cleaned or repaired.


Inspection Chambers & Bases are normally situated at one of three points in a drainage system.

  • Where a branch drain joins a main drainage pipe in the system
  • When there is a straight run of piping for more than 22 metres
  • Where a drain or sewer pipe changes direction horizontally by more than 30 degrees

As well as giving access to drains and sewers, manhole chambers are an important temporary storage point for water. They allow water to build up in the drainage system rather than flood out straight away.

While working on pipe systems, drainage engineers may deliberately block a pipe and use the manhole in the same way, to store waste water before letting it flow away once the drainage task is complete.