Before we get too, too, smug about this if you view the Manhattan
skyline, particularly downtown (e.g., SOHO/Tribeca) you'll see
house-sized water tanks on many, many buildings, particularly 3-10
story older buildings. I assume due to inadequate water pressure but I
honestly don't know why they're there, but they're all over.
I don't know if they're quite large enough for the proposed use, but
their existence would seem to defy most of the objections asserted
below.
It's my understanding that these tanks exist for the purpose of
providing adequate water pressure for residential use (e.g. showers,
faucets, toilets, etc.) I don't think they could possible hold even a
small fraction of the water necessary for emergency power generation.
