I have the same (maybe 15, it’s the diaphragm pressure tank). At any rate, you might be interested in a hand pump that works in unison with your well pump in case your run out of fuel for the generator or the generator just decides to quit.
I was checking out this one of these types myself:
http://flojak.com/?gclid=CN6QzMj06roCFZMDOgodsHMAjg
I doubt we'll ever need it, since we have 2 backup generators. With our stored water, holding tank, and hot water heater we have 105 gallons. We have 165 gallons in rain barrels.
Hubby is in the process of putting up a swimming pool to hold water for our garden-about 4000 gallons. We'd really like to have a cistern, but there again, that's a bit too pricey.