I try to keep some food at home (probably 2 weeks), it's just the normal food so it's rotating naturally. It's also helpful for weird local events that are very rare, but not unheard. (Hi from Argentina!)
I should keep more water, but I'm too lazy. I have only probably only two days that is too few.
If I had time, I'd pick some iodine pills. They are small and have a long shelf life.
Anything else is too difficult or too far from my control.