Spanish to English Other Poetry & Literature

Which would be the right English term for "pila"? In Central America mostly every house has one, it's like a kind of water tank. I'm translating a book and the author talks a lot about this particular thing, and since it's very relevant to the plot, I don't want to translate it as "water tank" or something like that. Isn't another way to express this in English? It's not the same one used for religious purposes. It's just a water tank that every family has to keep water.
Thanks a lot