Watch CBS News

Why aren't manholes flush with the street?

Good Question: Why aren’t manholes flush with the street?
Good Question: Why aren’t manholes flush with the street? 02:36

MINNEAPOLIS -- Drivers hit bumps in the road almost every time they drive. Sometimes it's a pothole. Others it's a manhole cover that's a few inches above or below the ground.

So, that had Bruce from Eden Prairie wanting to know: Why aren't manhole covers flush with the street? Good Question.

To answer this question, we turned to Kevin Danen, a sewer operations engineer with the City of Minneapolis. First, he explained what's underneath our roads.

"Under the street, you'll find gas, electric, water," he said. "You have sanitary sewer and the other manholes are connected to our storm system."

The manholes are the only easy way to access all this infrastructure that sits in the public right-of-way.

So, why are the manholes usually placed in the middle of the road? Danen points to three reasons.

First, he says crews purposefully try to keep them out of the wheel paths of the cars so they're placed in between the lanes.

"That puts extra stress on our manholes, all the trucks that drive over them," he said.


Second, Danen says the middle placement makes it easier for their large equipment to access the manholes to do repairs or maintenance. By parking the in the middle of the road, they can avoid parked cars, bikes or snow.

The third reason has to do with the fact that Minneapolis homeowners are responsible for their sewer line from the home to the street. By placing that line in the middle of the street, the distance of the lines are more even for odd and even neighbors.

"When we lay a sewer line, we try to make the financial burden equal with all the properties on both sides of the street," he said.

If a manhole isn't centered, that's generally because there's already too much infrastructure running down the middle of the road or the roadway has been realigned (ex. new bike paths) without moving the manholes.

But, back to the original Good Question: Why aren't the covers flush with the road?

"A variety of reasons," Kevin said.

First, years of sand and salt can degrade the manhole so it will sag and sink over time.

Second, if crews have repaired or resurfaced the road, the don't always raise or lower the manhole covers to make them even with the ground.

Danen said people can call Minneapolis 311 to report a manhole cover that's problematic. Crews will come out to inspect and usually have ways to adjust the covers as they move over time and Minnesota weather.

"It's just the nature of the beast," he said.

View CBS News In
CBS News App Open
Chrome Safari Continue
Be the first to know
Get browser notifications for breaking news, live events, and exclusive reporting.