We designate the spirit of the well as 'she' because in most of her personifications she takes a female form, though not invariably. She appears in many guises - ghost, witch, saint, mermaid, fairy, and sometimes in animal form, often as a sacred fish - and her presence permeates well lore, and indeed water lore generally.
Colin Bord
fairy, ghost, holy-well, holy-wells, mermaid, sacred-fish, saint, wa-ter-divinity, water, water-god, water-goddess, witch