We currently have city water. Luckily, I have an absolutely enormous basement in this old house. I store water in everything that is safe to store in. We don’t drink soda pop but our neighbors do so we get their 2-liter bottles. Every week I spend $5 picking up 1-gallon water jugs from the store. I also have a water-bob for the tub and a few larger containers I purchased to test out.
One thing a person pointed out to me years ago – if you are a canner, instead of storing your jars empty, you should store them filled with water. I do not seal them for this – I just put the lid on my clean jars full of water. When I need them for canning, I dump the water into the pot and use it for the process. If I need them for an emergency, boom, loads and loads of water just sitting here waiting for me.