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PMG manholes in a city street, Perth, Western Australia.
Manhole in Belo Horizonte, Brazil.
This is a sewer manhole, exposed during construction. Typically, only the top ring and manhole cover (not pictured) would be visible.
Manhole cover of precast concrete in Germany

A manhole (alternatively utility hole, cable chamber, maintenance hole, inspection chamber, access chamber or confined space) is the top opening to an underground utility vault used to house an access point for making connections or performing maintenance on underground and buried public utility and other services including sewers, telephone, electricity, storm drains and gas.


The manhole opening is protected by a manhole cover (also known as a "biscuit"[citation needed]), a flat plug designed to prevent accidental or unauthorized access to the manhole. Those plugs are traditionally made of metal, but may be constructed from precast concrete, glass reinforced plastic or other composite material (especially in Europe, or where cover theft is of concern).

Manholes are usually outfitted with metal, polypropylene, or fiberglass steps installed in the inner side of the wall to allow easy descent into the utility space. Because of legislation restricting acceptable manual handling weights, Europe has seen a move toward lighter weight composite manhole cover materials, which also have the benefits of greater slip resistance and electrical insulating properties.

The access openings are usually circular in shape to prevent accidental fall of the cover into the hole.

Manholes are generally found in urban areas, in streets and occasionally under sidewalks. In rural and undeveloped areas, services such as telephone and electricity are usually carried on utility poles or even pylons rather than underground.

Composite manholes[edit]

Composite (fiberglass) manholes are commonly used in applications where infiltration, exfiltration, or corrosion by hydrogen sulfide (from sewer gas) are a concern, or where structures need to be factory integrated into a manhole before placement.

Structures commonly integrated into composite manholes include:

  • Flow inverts[1]
  • Flumes[2]
  • Drop structures from higher elevation flows to lower elevation discharge pipes

Occasionally, composite manholes will integrate:

  • Weirs[3]
  • Storm water screening structures[4]
  • Sewage grinders[5]
  • Energy absorbing structures to dissipate undesirable flow stream turbulence or velocity[6]

Hazards caused by stray voltage in manholes[edit]

In urban areas, stray voltage issues have become a significant concern for utilities. In 2004, Jodie S. Lane was electrocuted after stepping on a metal manhole cover, while walking her dog in New York City.[7] One solution is the Electrified Cover Safeguard invention, which is an on-site, real-time stray voltage warning system which is being used in the street lights in New York City and is also being tested by ConEd and other utilities and municipalities in England, Europe, and Japan.[citation needed]

See also[edit]



  • Isles, Paul (2010). "Dover Engineering Works". Dover Life Magazine

Further reading[edit]

  • Ascher, Kate ; researched by Wendy Marech (2007). The works : anatomy of a city (Reprint. ed.). New York: Penguin Press. ISBN 978-0143112709. 

Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Manhole — Please support Wikipedia.
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3887 news items

Sat, 19 Apr 2014 16:26:15 -0700

A manhole is overflowing releasing nearly 25 gallons of water a minute. City officials says the underground sewer system is overloaded after heavy rains. Residents should avoid contact with the storm water. Copyright 2014 WALB. All rights reserved.
Times of India
Sat, 19 Apr 2014 17:33:45 -0700

PATNA: Patna Municipal Corporation (PMC) commissioner Kuldip Narayan has asked the executive officers (EO) and executive engineers (EE) of all circles to take strict action against the officials concerned if they failed to replace the damaged covers of ...
The Onion (satire)
Thu, 17 Apr 2014 08:00:00 -0700

NEW YORK—Standing mystified in a crowded intersection, Verus Attius Glabrio, a Roman centurion who emerged from a manhole in the middle of New York's Time Square, is in for a wacky adventure, sources confirmed Wednesday. Reports stated that ...
Fri, 18 Apr 2014 14:22:30 -0700

A neighbor who lives in one of the two homes said he doesn't understand why the city hasn't done anything besides the smoke testing to try and prevent the manhole from overflowing. "I think that we, as taxpayers, shouldn't have to live like this. In ...

American Live Wire

American Live Wire
Wed, 16 Apr 2014 09:52:30 -0700

Everywhere you look the media is pushing you telling you who to follow, what to watch and when to watch it. You're even sometimes told how to do it all. Truth is, here at American Live Wire we do a bit of that too. The big difference is we also tell ...
al.com (blog)
Mon, 14 Apr 2014 19:41:38 -0700

A manhole cover on St. Francis Street, between Water and Royal streets, was being lifted by the rushing water under it. Evans said he saw a car roll over it, only to be hit by the popping manhole cover. He said the cover was lifted even higher than ...
Coquitlam Now
Thu, 17 Apr 2014 15:41:15 -0700

The final party named in a lawsuit involving a Coquitlam man who allegedly fell into a manhole has filed a response to his civil claim. The City of Coquitlam has denied all of the allegations made by Albert Trim. In a civil suit filed on Feb. 5, Trim ...
Thu, 10 Apr 2014 14:30:35 -0700

WSA employees Tremayne Price and Nick Lockridge remove a manhole cover to install a flow meter in a storm drain along Lee Road Thursday afternoon. The covers have been targeted in recently by thieves and in some cases their disappearance led to ...

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