# Why does steam rise from manholes in Denver?

**URL:** <https://boards.straightdope.com/t/why-does-steam-rise-from-manholes-in-denver/749769>\
**Category:** Cecil's Columns/Staff Reports\
**Created:** [March 21, 2016, 2:50pm UTC](https://boards.straightdope.com/t/why-does-steam-rise-from-manholes-in-denver/749769 "2016-03-21T14:50:36Z")\
**Posts on this page:** 1\
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**Author:** ![Atamasama](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/atamasama/32/12961_2.png) [@Atamasama](https://boards.straightdope.com/u/Atamasama)\
**Post date:** [March 21, 2016, 5:31pm UTC](https://boards.straightdope.com/t/why-does-steam-rise-from-manholes-in-denver/749769/3 "2016-03-21T17:31:47Z")

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> [@monterey86](#):
>
> - Why does the steam not stay in the pipes and escape through manholes?

For the same reason your roof might leak. Also, from water **on** , rather than **in** the pipes.

> **[We'll be back shortly](https://www.coned.com/steam/kc_faqs.asp)**
>
> 500 ERROR

_Planting Steam can come from manholes for several different reasons. The most common is water infiltration into the manhole. Water comes in contact with the hot steam main and causes vapor. Another source is leaks, either within the manhole or on buried piping between manholes. There is no “natural” venting process_

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