Why Manhole Covers Are Round

February 14, 2024

A manhole cover is much more than just a pretty piece of metal — it’s one of the most important safety and maintenance tools for your city’s underground infrastructure. They help keep people out of dangerous and dirty spaces, make it easier to identify the type of utility below them and are often equipped with tamper-resistant locks to prevent unauthorized entry into sewers or other confined spaces.

Most of the time, you’ll see round manhole covers in cities and towns around the world. However, if you were to walk down the street in some places, you might encounter covers that are square, rectangular or even oval. So why are these covers round, when other shapes could work just as well?

As it turns out, there are a few reasons why most manhole covers are round. One is that the shape helps them resist the compression of the Earth around them. This is because of the way that a circle sits on top of the rim of the hole, with each point of its edges being an equal distance from the center. This creates a strong, sturdy structure that can withstand the pressure of heavy vehicles.

Another reason is that it’s simply easier to move round covers from place to place than any other type of cover. The fact that they’re round means that they can be rolled rather than lifted and then pushed from the side, which makes it easy for workers to get them in and out of trucks when it comes time to do maintenance on the underground utilities. There is also a financial aspect to it, as the circular design means that there is less surface area than there would be on a square manhole cover of the same size, and this cuts down on manufacturing costs.


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