Here's a very clever soft sided watering can that's called the Squish. It helps you save space and it is easy to store when it is empty.

The watering can was made by Marc R., and he is working with Quirky to make it a reality. The Squish expands from just one-inch thick when empty and stored to eight-inches across when full of water. It can hold up to a full gallon of water, and features a folding spout that helps minimize the Squish's footprint even further.[Quirky via InventorSpot]