Lots to take in but it can and sooner or later will happen and then we have a whole new host of other issues because of it. How soon depends on how high up you are from the lines.
One of the things I have been doing is reading up on possible things we might have to be doing. We have 5 gal buckets with toilet lids just in case. But also an outhouse. Yes, been there used those and they can stink. So one thing I am thinking about buying and storing in shed is type S-Hydrated lime. You just sprinkle some in bucket or can after you go, and it will keep the smell and flies down and out. So that is on my need to get list.