Essay: “The Terror of the Water-Tank”, William Hope Hodgson, 1907.
This story has the tone of a detective story – there are murders and an investigator (though not a professional, just the relative of a victim) – told in a very matter-of-fact way. There is a weird element – an eel-like killer monster in a town’s water tank.
The story’s concept lingers in the mind as a curious bit of weirdness though the final line on the value of cleanliness sort of undercuts that with its black humor.
You can see this story as Hodgson bringing one of his nautical horrors – he’d already published several of his Sargasso Sea stories – on to dry land.