Water is a top priority as well. We store an abundance of water. You should store water for ALL your pets and livestock to drink from just in case in addition to the human supply.
We have a filter for our use to obtain water on the go, but there is no reason you can’t use the same filter to replenish water for your pets. Just like us, pets have about 3 days without water to survive. It would also be a good idea to have a bowl for drinking and feeding with your supplies.