Once you have your Storable Food, you need to look at Water Storage / Water Filtration.

Water storage:

You can store water while it is plentiful and much cheaper than when a crisis hits (natural disaster or water shortage/outage).

Gallon jugs and 2 Liter bottles are a good way to store water in small quantities, but does not stack very well.

For large quantities of water, I would look at something I found on Bob's site

ReadyMadeResources.com

WaterBrick

Stackable Rectangular blocks which interlock for stability.
Capacity: 3.5 gallons each.
Dimensions: 9″ W x 18″ L x 6″ H.
Easy to grip comfort handle.
Can be used for water or foods like rice, beans, or anything you want to keep safe and dry from the elements.
The container is sealed with the easy grip full rubber gasket creating a tight seal.
FDA approved, BPA free.
WaterBricks are made of made from virgin resin or recycled, rugged, high density polyethylene (HDPE).

Water Filtration:

With chemicals and other things in the water today I filter my water even when there is not a crisis.

Flint had very high levels of Lead in the water for many years, even after someone complained about it the city didn't fix it. This goes unreported around the country.

Not only did they not fix the problem, they continued to charge the people for bad water.

I personally use the AlexaPure Pro gravity fed water filter. With gravity fed you can take it anywhere with you, no need for running water or electric.