Dagny, you might also take note of the expiration of one of your new bags of dog food, to get an approximation of how long it CAN last (probably not desirable under normal conditions, but...).

If the expiration date is decent (possibly shorter than the poorer foods available at most grocery stores and WallyWorld), and if you have a place to store it that vermin couldn't get to, maybe you would want to spring for an extra bag, which you would naturally rotate.

Excellent choice of food, BYW. I hear it makes your brown eyes browner.

Re: water... for ease in figuring, you might just plan on storing the same amount for her as you do for yourself. Her water and your water is likely to be the same, so you would probably open a gallon and share it. If you had overestimated her requirements, it could only be to the good for both of you.

For people who use the pet foods that contain a lot of filler foods (corn, wheat, rice, barley, etc), you dog probably requires more of those foods to maintain weight, as those grains are actually chicken feed, not dog foods, and often aren't digested (large, soft stools are one sign). If you plan on storing the cheap foods, they will actually require more space than a more nutrient-dense food will. I would consider it a waste of space, but YMMV.

Sue