If water goes away, many millions will die as it takes so much to keep a body living. And, if it's all used to drink, and there is no cleaning of bodies or surfaces, infection will make them die sooner. Water is number one to stay alive and healthy.
I don't think you have talked about your water sources. Do you live near a body of water? I assume you have water purifiers.
Water is a real and serious worry for me. It is so serious it almost out ways everything on the side that that says bug in. The river here will be a ‘hunting ground’ of zombies and or predators, that is if the banks aren’t ablaze from careless fires. Even then I think that sooner or later the water will be unusable even if you can get to it especially in the dry season which is most of the year here.