Symbolism, Imagery, Allegory
Water is never just water, is it? And in a Toni Morrison novel, it's definitely not just water.
Remember when Beloved walks fully dressed out of the water and Sethe runs to the side of the house to release what seems like gallons of water from her bladder? Yeah, that's about as clear a (figurative) (re)birth scene as you can get. In fact, Morrison pretty much lays it out for us:
But there was no stopping water breaking from a breaking womb and there was no stopping now. (5.5)
In case you missed it the first time around, our narrator shoves the water-breaking image right in our face. But who's being reborn? Beloved? And is she being reborn literally or figuratively? Good luck parsing that one out.
Water also loves to signify baptism and all the "good" things that come along with it, like redemption. Beloved gives us her take on a little baptismal moment:
I am standing in the rain falling the others are taken I am not taken I am falling like the rain is I watch him eat inside I am crouching to keep from falling with the rain I am going to be in pieces he hurts where I sleep he puts his finger there I drop the food and break into pieces she took my face away (22.7)
Okay, so maybe feeling saved or not being "taken" isn't all that great a feeling. After all, this isn't a real baptism. But it does put into question the idea that life is sacred. Here, living and being saved means that Beloved is just vulnerable to other forms of attack—in this case, molestation (or worse).
Yep, water can take on other, darker meanings. It signals literal death, especially the deaths of all those who drowned on the Middle Passage.
P.S. Do you think water picks up on Beloved's fluid nature and her general lack of boundaries? Even the way she speaks is fluid—see ya later, punctuation.