Is it economically viable to treat collected rainwater to be drinkable?

[allegrif]

This is something I've been considering for a while. Collecting rainwater seems like almost common sense, but most of my potential uses for it would require it to be cleaned. Obviously this can be done, but will it break the bank? Perhaps someone might be able to send me in the direction of a figure or quote estimate?

[Zarostulus]

You're looking at about £320 inc. VAT for the full solution. I'd recommend it though, it's a great long-term investment.