Editing Urban exploration (section)

===Sewers and storm drains===
[[File:St Paul storm drain.jpg|thumb|left|160px|Storm drain outfall in [[Saint Paul, Minnesota]]]]
Entry into [[storm drain]]s, or "draining", is another common form of urban exploration. Groups devoted to the task have arisen, such as the [[Cave Clan]] and Darkside in [[Australia]]. Draining has a specialized set of guidelines, the foremost of which is "When it rains, no drains!", because the dangers of becoming entrapped, washed away, or killed increase dramatically during heavy rainfall.

A small subset of explorers enter [[sanitary sewer]]s. Sometimes they are the only connection to caves or other subterranean features. Sewers are among the most dangerous locations to explore owing to the risk of poisoning by buildups of toxic gas (commonly [[methane]], [[hydrogen sulfide]], or [[carbon dioxide]]). Sewers can contain viruses, [[bacteria]], [[protozoa]], and [[Parasitic worm|parasitic worms]]. Protective equipment is recommended for people who enter sewers.<ref>{{Cite web |last=Water |first=Municipal Sewer and |date=2020-06-22 |title=How to Keep Sewer Workers Safe |url=https://www.mswmag.com/editorial/2020/07/how-to-keep-sewer-workers-safe |access-date=2022-12-09 |website=Municipal Sewer and Water |language=en}}</ref>