The water system shuts down because the tanks aren't reserve supply they're pressure support.
And solar plus storage will keep you running for maybe a week if you're conservative and mostly don't use anything...which doesn't help you if it's months till replacement.
But yes, unless you spend serious money (own sewer, water from underground etc), it's basically solution for "the power pole is down", not any grid wide problems.
You'd be better off with an air sourced hear pump for hot water anyway - the one in my house uses less power then my dehumidifier.
It is often the case (at least where I live) that having a septic system and well is far more economical than obtaining a property with access to city utilities.
They're off grid, and can be swapped out if the PV panels or immersion pumps fail.
Ideally you should be pumping into tanks in any case, for the buffer, and those tanks can be placed on a hill to gravity feed .. or pump with a motor.
Here's a typical setup, sans old windmill: https://youtu.be/iZAMm_S3GNQ?t=383
(same rough area (W.Australian wheatbelt) not our land)