Water-related weirdness has featured on here quite a lot. Large, still bodies of water, especially reservoirs, seem ominous. Canals can be the scenes of nightmares.
Human diversions of water via sluices, weirs, mills, races, tanks and locks seem to attract more hauntings than natural streams.
If we extend it to cisterns, we get all those toilet-ghosts, who chase you downstairs. Not to mention those imperfectly-closed valves, which mutter and hiss at you for ages after flushing!
In my primary school, there was a storeroom - it was mainly a repository for old desks - where I might, occasionally, have to venture. By choice? By instruction? Maybe the horror of it led me to step inside from time to time, just to confirm how evil it felt. Kids do that.
It was a long, windowless place, essentially just a slice off the adjacent classroom; its main purpose appeared to be to accommodate a large header-tank, which occupied the top part of one end of the space. Water-noises would accompany any visit. It did not seem to leak but a dank air hung over the room; it was dispelled when the door was shut. All just a step away from a noisy class of kids!