I have a rain barrel in my basement, with an aquarium filter in it that I run occasionally when it gets scummy. It might not survive an earthquake, but those are pretty unlikely in MN. It was originally intended as a backup for my outdoor rain barrel which I use for plants, but then I realized it's also good emergency water. If I have to use it for drinking water, I'll pull the water filter out of my camping gear.
I also have a couple 2.5 gallon Reliance water jugs that I keep full, with a dash of bleach in them. The water in them came from my RO drinking water system, so it's quite clean. They're under a WW2 style steel desk, so they'll probably survive my house being destroyed by a tornado.