First and foremost, having a rain barrel underneath your downspout will allow you to collect plenty of natural rain water so that you can keep your gardens watered during a water ban. Rain water is great for plants, being that it’s usually soft and free of dissolved materials. Not only will you have water available during a water ban, you’ll also free yourself from having to use tap water, saving you a good chunk of change on your water bill. Not to mention, cold tap water can “shock” your plants.