Providing enough water to livestock and large animals is a necessary daily chore. Stock tanks are the most common container used for containing drinking water for them. Stock tanks can be made from steel, UV protected plastic and even aluminum. Plastic has its advantages in that it does not get rusty. Rust can cause problems for animals if ingested in water. Rust is in fact iron and iron if ingested in higher than recommended quantities is not healthy.
Other containers I have seen used for water tanks are stainless steel drums, cut in half and the edges protected so they will not cut the animal and old claw foot bath tubs. The bath tubs are often enameled and if cared for properly will not chip and expose the underlying steel, which will rust.
The photo at the top of this post shows what you can do with a stock tank……….make it into a water garden. It makes a great place to keep Koi or goldfish. You will need to provide some sort of filtration system if you have more than just a few fish. Koi and goldfish poop a lot and that needs to be removed from the tank to prevent a build up of gases in the water.