We have moved so far from communal water supply and sanitation to private infrastructure that we don't have many options when that private infrastructure breaks down. If your home plumbing breaks and you can no longer get fresh water from the tap, you can't just wander down to the local well instead. There's no backup plan. You have your own water at home or you don't have water. You have a working toilet at home or you don't go, unless you have very understanding neighbours or a nearby shopping centre. I suppose, if you have your own back yard, you could dig a pit latrine.
In times of natural disaster, this becomes a wide-scale problem, and the only way I've seen it solved is with water delivery trucks and portable toilets. So at least in that disaster time, everyone has the same problem and it's able to be handled by a mass solution. If you're the only one with a problem, though, then your solution options are very limited.
Mokalus of Borg
PS - Just don't let your plumbing break down, I suppose.
PPS - If it's up to you.