How would someone living in a city have access to unlimited water?
You will need a water filtration system - they are not expensive.
Most cities are located on rivers - you get a 5-gallon pail full and take it back to your house and treat/filter it.
You will need to do that every day - just like in olden times....
“How would someone living in a city have access to unlimited water?”
Set up a downspout from your gutter to a couple of 30 gallon plastic garbage cans. Cover the top with screening material to filter out the big stuff and then get a Big Berkey water filter to purify it. Once the electric goes off so will your tap.