I've always washed the water bowl in washing-up liquid and rinsed well and dried it, then put fresh water in.
I've recently read that you can taint the bowl this way, although it is recommended in another book. Sometimes my cavs used to go outside to drink from our pond and I wonder if this is why.
I've just been refreshing on puppy care, as I might be having a new friend soon and I came upon the water bowl issue.
Would salt and vinegar be better to wash the bowls? Or bicarb? What would you advise please.