Well, actually a reservoir. With full planning permission to turn it into an underground eco home.
Frodo would love it.
The reservoir is within about half an acre of land in a pretty location on the edge of one of Hull's poshest villages - Elloughton - and with decent site access.
The building itself is one big (1600sqft) space, with an entrance. And the plans extend that to 2400sgft to build in a three-bed home with courtyard and parking.
Details and more pictures here.