A manhole (utility hole, maintenance hole, or sewer hole) is an opening to a confined space such as a shaft, utility vault, or large vessel. Manholes, typically protected by a manhole cover, are often used as an access point for an underground

public utility A public utility company (usually just utility) is an organization that maintains the infrastructure for a public service (often also providing a service using that infrastructure). Public utilities are subject to forms of public control and ...

, allowing inspection, maintenance, and system upgrades. The majority of underground services have manholes, including

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

, sewers,

telephone A telephone, colloquially referred to as a phone, is a telecommunications device that enables two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most ...

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...

storm drain A storm drain, storm sewer (United Kingdom, U.S. and Canada), highway drain, surface water drain/sewer (United Kingdom), or stormwater drain (Australia and New Zealand) is infrastructure designed to drain excess rain and ground water from i ...

district heating District heating (also known as heat networks) is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements such as space heater, space heating and w ...

, and gas. Manholes are generally found in urban areas, in streets and occasionally under

sidewalk A sidewalk (North American English), pavement (British English, South African English), or footpath (Hiberno-English, Irish English, Indian English, Australian English, New Zealand English) is a path along the side of a road. Usually constr ...

s. In

rural In general, a rural area or a countryside is a geographic area that is located outside towns and cities. Typical rural areas have a low population density and small settlements. Agricultural areas and areas with forestry are typically desc ...

and undeveloped areas, services such as telephone and electricity are usually carried on

utility pole A utility pole, commonly referred to as a transmission pole, telephone pole, telecommunication pole, power pole, hydro pole, telegraph pole, or telegraph post, is a column or post used to support overhead power lines and various other public util ...

s or even pylons rather than underground. In Australia, ''manhole'' also commonly refers to an access hatch used to get access from a room or hallway into the ceiling cavity of a building. These manholes are typically around square.

Construction

Manhole closings are protected by a grating or manhole cover, a flat plug designed to prevent accidental or unauthorized access to the manhole. These covers are traditionally made of metal, but may be constructed from

precast concrete Precast concrete is a construction product produced by casting concrete in a reusable molding (process), mold or "form" which is then cured in a controlled environment, transported to the construction site and maneuvered into place; examples i ...

, glass reinforced plastic or other

composite material A composite or composite material (also composition material) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a ...

s (especially where cover theft is of concern). 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. Manholes are usually outfitted with metal,

polypropylene Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer Propene, propylene. Polypropylene belongs to the group of polyolefin ...

, or

fiberglass Fiberglass (American English) or fibreglass (English in the Commonwealth of Nations, Commonwealth English) is a common type of fibre-reinforced plastic, fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened i ...

steps installed in the inner side of the wall to allow easy descent into the utility space. Manholes are usually round, primarily because roundness is the best shape to resist the compression of the earth; covers are round because they are easier to move by rolling, and they can't fall into the opening. But in the United Kingdom they are nearly always square, or rectangular, in shape, at least at street level. Manholes can also be found in a triangular shape (e.g. in

Cambridge Cambridge ( ) is a List of cities in the United Kingdom, city and non-metropolitan district in the county of Cambridgeshire, England. It is the county town of Cambridgeshire and is located on the River Cam, north of London. As of the 2021 Unit ...

, and surrounding villages).

Composite manholes

Composite (

) manholes are commonly used in applications where infiltration, exfiltration, or corrosion by

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is toxic, corrosive, and flammable. Trace amounts in ambient atmosphere have a characteristic foul odor of rotten eggs. Swedish chemist ...

(from

sewer gas Sewer gas is a complex, generally obnoxious smelling mixture of toxic and nontoxic gases produced and collected in sewage systems by the decomposition of organic household or industrial wastes, typical components of sewage. Sewer gases may incl ...

) are a concern, or where structures need to be factory integrated into a manhole before placement. In these manholes, the entire underground enclosure is constructed of some composite material, in addition to the cover. Structures that can be integrated into composite manholes include: * Flow inverts * Flumes * Drop structures from higher elevation flows to lower elevation discharge pipes *

Weir A weir or low-head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the water level. Weirs are also used to control the flow of water for outlets of l ...

s * Storm water screening structures *

Sewage Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater that is produced by a community of people. It is typically transported through a sewerage, sewer system. Sewage consists of wastewater discharged fro ...

grinders * Energy absorbing structures to dissipate undesirable flow stream turbulence or velocity

Hazards caused by manholes

In urban areas, damaged or uncovered manholes and stray voltage issues have become a significant concern. On January 16, 2004, Jodie S. Lane was electrocuted after stepping on a metal manhole cover, while walking her two dogs in New York City. On December 3, 2020, Justin Carey, a 49-year-old special education teacher, was injured after stepping on a broken manhole cover on Route 111 in Smithtown. As he exited his parked car near the Route 347 intersection, the split cover gave way, causing his left leg to fall into the hole. He suffered a strained Achilles tendon and a bruised knee.

Sewer manhole location

The location of a sewer manhole must be carefully considered to ensure that the drainage system is effective and easy to maintain. According to design standards, the distance between two manholes is typically between 7 and 20 meters, depending on the specific characteristics of the project. In cities, the distance is 20 meters per manhole, while in industrial or commercial settings it is 10-15 meters per manhole. The distance between manholes in homes or restaurants is typically 7-10 meters.

Gallery

Open Manhole and Cover Mid-City New Orleans.jpg, A round manhole in New Orleans, and its cover Bueirocemig.JPG, Manhole cover in

Belo Horizonte Belo Horizonte is the List of largest cities in Brazil, sixth-largest city in Brazil, with a population of around 2.3 million, and the third largest metropolitan area, containing a population of 6 million. It is the List of cities in Sout ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

Cambridgeshire Manhole.jpg, Manhole cover in Sawston,

Cambridgeshire Cambridgeshire (abbreviated Cambs.) is a Ceremonial counties of England, ceremonial county in the East of England and East Anglia. It is bordered by Lincolnshire to the north, Norfolk to the north-east, Suffolk to the east, Essex and Hertfor ...

Manhole.jpg, Installation of a sewer manhole. Upon completion, typically only the top ring and cover (not pictured) would be visible. - Manhole cover in Germany -.jpg, Manhole cover of precast concrete in

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

Manhole without manhole cover in Villebon-sur-Yvette 4.jpg,

Storm drain A storm drain, storm sewer (United Kingdom, U.S. and Canada), highway drain, surface water drain/sewer (United Kingdom), or stormwater drain (Australia and New Zealand) is infrastructure designed to drain excess rain and ground water from i ...

manhole without cover in

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

ManHoleDoorFoundersHallGirard1840.jpg, "Man Hole Door" at Girard College,

Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...

, constructed in the 1840s Openchannelflow-domed-metering-manhole.JPG, An open packaged metering manhole made of fiberglass before installation Sasa manhole cover.jpg, Manhole cover in

Kibbutz A kibbutz ( / , ; : kibbutzim / ) is an intentional community in Israel that was traditionally based on agriculture. The first kibbutz, established in 1910, was Degania Alef, Degania. Today, farming has been partly supplanted by other economi ...

Sasa, Israel File:HAIFA DOWN TAWN.jpg, Manhole cover in downtown of

Haifa Haifa ( ; , ; ) is the List of cities in Israel, third-largest city in Israel—after Jerusalem and Tel Aviv—with a population of in . The city of Haifa forms part of the Haifa metropolitan area, the third-most populous metropolitan area i ...

Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...

Golden manhole cover Tel Aviv.jpg, Painted gold Manhole cover in

Tel Aviv Tel Aviv-Yafo ( or , ; ), sometimes rendered as Tel Aviv-Jaffa, and usually referred to as just Tel Aviv, is the most populous city in the Gush Dan metropolitan area of Israel. Located on the Israeli Mediterranean coastline and with a popula ...

References

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