Water attracts and retains ghosts. But why?
Many haunted houses have a nearby water source. It could be coincidental: after all, most old houses and buildings are built near natural bodies of water. However, what is uncanny is that a lot of these houses have a high level of paranormal activity. Not all of the ghosts originate from the house, either. Spirits are attracted to ponds, rivers, moats, seas, lakes, and oceans.
Ghosts need energy.
One of the reasons that ghosts may be attracted to lakes, river, and oceans is that they use the energy. Flowing water has an electrical charge. It can be harnessed and used by people. However, it can also be used by ghosts. They really only need a little bit of energy, and water has a negative charge that attracts and invigorates spirits.
Big houses are easy to find.
It wasn’t until recently in human history that people could have long-lasting structures that served as homes. Farms would be few and far between, and big homes were reserved for the rich. Peasant houses made of cob and stone would eventually wear away or be taken down. Huts would burn or wear away, too. Thus, anyone who needed or wanted a long-lasting structure would build it on the river or lake where they could get a fresh supply for drinking and washing, and sometimes transportation.
And thus, a spirit looking for a place to stay may be energized by the water and look to the only standing structure in the area: the house, castle, or mill house right by.
Ghosts don’t find their way easily.
Often times, in movies you’ll see ghosts moving through fog or the dark. For them, this is what being trapped on Earth is like: they can only move when energized, and many of them can’t navigate the world most of the time. They don’t have the energy, or they don’t know the landscape. Thus, when they do get energy, they can better move around, but not for long. Even ghosts don’t want to wander outside; after all, they were once people. Thus, they go to the nearest structure, and that’s as far as they can go.