My cats don't have bladder stone problems, but we did have a peeing problem with one, and they said her urine was very concentrated, so I started adding more water. We have always have a fountain, and I do need to refill it regularly, but rarely actually see either of them drinking from it. I wonder how much is lost to evaporation.
Anyway, I have buckets of water in my bathroom that I fill with shower water while it heats (takes 2 gallons to get hot, so I fill buckets to water the plants with) The cats are ALWAYS drinking out of these. I have not started leaving buckets elsewhere, but I have considered it just to encourage drinking! So definitely having water in different locations is good for the cats.