This is my long-term solution to an emergency supply of water. I have hooked up these "water cubes" to my gutters so I can catch a lot of rainwater. There are a lot of products out there for rain barrel connecting, diverting, filtering, etc., but I did most of mine with stuff I salvaged for pretty much free, have less than $50 tied up in the materials that it took to hook up 3 containers.
IN THIS AREA these "water cubes" seem to be in short supply. There's a place close by that used to have them for $100 but they are out and don't know when they will have more. I'm looking for more of these if anyone knows where some are.
AUTHOR ADDED: SORRY, I MEANT TO POINT OUT THAT THIS WATER WILL OBVIOUSLY HAVE IMPURITIES IN IT. THERE ARE A LOT OF GOOD COMMENTS ABOUT WHAT MIGHT GET FLUSHED INTO THE TANK ALONG WITH THE WATER FROM THE ROOF, NOT TO MENTION THE TANK ITSELF. THIS WATER WOULD NOT BE FIT FOR HUMAN CONSUMPTION UNLESS IT IS SERIOUSLY PURIFIED FIRST. SEE MY PAGE WITH THE WATER PURIFICATION IDEA, I HAVE ADDED PICS AND INFO TO HELP EVERYONE FIND THE STUFF I USED.