You don't need 2k calories a day in an emergency.
You can survive on 1200-1500 calories a day.
I still don't advise going in 100% on rice as beri-beri is an issue (or heavy metal issues if you go all brown rice).
A good mix of canned goods, dried goods and reliable water will help. Even in a shortage you will probably have some access, but limited access.
I strongly advise against bottled water for emergencies. It is the worst possible solution for cost/size/availability. You can buy 6 gallon aquatainers and fill them with tap water for an easy (and useful for camping) solution. Rotate every six months and you don't need secondary treatment.
Otherwise a food grade 55 gallon drum is $100 and you can fill it from your tap. You will want secondary treatment options if you plan to rotate just every 2 years, and you still need a smaller intermediary vessel.