to make sure they work and wont break,so you know if its broke or not,so the animal can stay hydrated,that you can keep an eye on the system,human uses require fresh water,water,to keep them clean and tidy,so you know if there is a problem,to clean things,to make sure they have fresh water,to survieve,to help the animals to stay alive,so animals can get enough water,so animals have enough water,if it work if the water is coming out of,people can drink water,hydrate,so they dont breakkkkk,so the animal can have water,to feed animals,to know how to use the water systems,