By Jennifer Copley (Last Updated 16 July 2011)
Cats often perplex their owners by turning their noses up at a freshly filled bowl of water but drinking happily from muddy puddles, glasses of water that have been sitting around overnight, or even the toilet.
Cats have a far better sense of smell than people, which affects their sense of taste as well, and some cats find the chlorine in tap water unpleasant. Standing water, such as that in the toilet bowl, is free of chlorine because the chlorine dissipates over time. And of course rainwater in outdoor puddles is free of chlorine to begin with.
Reference: Morris, D. (1987). Catlore. London, UK: Jonathan Cape Ltd.