According to Randall Munroe (the author behind xkcd.com) in his book ‘what if? 2’ a house sized cumulus cloud, which would be very small for a cloud, contains roughly one litre of water, which in turn weighs 1 kilogramm.
If you want to look it up and somehow find a version of the book online, this information is in the chapter about the largest thing you could theoretically eat in one sitting (it’s the cloud).