Does anyone make a UPS (uninteruptable power supply) powerful enough to run
a 1/2 HP - 240V submersible water pump?

We live in a rural area which means we have occasional power outages,
usually at the worst times. Unfortunately, when the power goes out, so does
our water supply. That means we can't wash up, flush the toilets, or even
get a drink of water when the power goes out. We're building a new house
that will have a wood stove as a means of backup heating. We could even
heat pans of water on the woodstove if we needed to for bathing, dish
washing, etc. But, we still need a supply of water that will last a day or
two.

I'm not interested in a gas generator as it would seldom be used, would
require maintenance, and would require that we hike out to the pump house
in the worst weather to start it up. In addition, we have a 250 gallon
pressure tank, so the pump really only runs a short time when needed to
refill the pressure tank.

So, I'd like to find a system that uses a battery and an inverter to power
the pump, with provisions to automatically keep the battery charged up when
we do have power. It should be totally self maintaining, no switches to
flip, no generators to start, etc. Just like a UPS you would use for a
computer, only large enough to run the 240V pump.

Any ideas who would make something like this?

Better yet, is there a way we could add additional pressure tanks or
something to ensure that we always have a large supply of water? It always
seems like we lose power just as the pressure tank is about empty. So, we
rarely ever have the full 250 gallons when the power goes out.

For what it's worth, our pump house is located about 150 feet from our
house. The pressure tank and all pump equipment is in the pumphouse, and
has it's own power separate from the house.

Thanks,

Anthony