- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 26 Mar 2018
A manhole, also known as an inspection chamber, provides access to underground utilities, most commonly sewer systems. This enables operatives to undertake inspections, make modifications, and carry out cleaning and maintenance.
Manholes are generally constructed where there is a change of direction and/or a change in gradient of the utilities, or where access is required for a specific maintenance purpose. They are typically positioned 0.5 m away from curb lines, preferably with the manhole cover positioned away from the wheel line of traffic.
The cover acts as a plug to protect the manhole and prevent unauthorised access. Covers can be circular, rectangular or square, and are typically made from metal or, less commonly, precast concrete, glass reinforced plastic, or a composite material.
Older manholes are usually fitted with steps on the inner side of the wall to allow easy access. Generally, if the manhole depth is less than 1 m, a step ladder is mandatory, whereas if it exceeds 2.5 m, a regular ladder must be fitted. More modern manholes may be designed so that physical entry is not required.
For more information, see Manhole chambers.
 Find out more
 Related articles on Designing Buildings Wiki
Featured articles and news
A new theory for managing large complex projects
A vision for digital highways
Finding stone to conserve historic buildings.
If it is not planned properly even a simple activity can kill.
A disgruntled or ignored stakeholder can easily derail your hard work.
Next generation cementitious materials
Still going strong...one of the great buildings of the 20th century.
Review of the bible for heritage assets and their management.
The David Lloyd Lymington Sports Village was 'Commended' in CIAT's 2018 AT Awards.
How do we make the smart city a reality?
Sir Nicholas Grimshaw has been awarded the UK’s highest honour for architecture.