A few years ago we invested in a high quality dc pump for our offgrid
water system. It was recommended we go with a solar force piston pump
with a 12v motor. Although it is a fine pump, and is much more efficient
than our old jet pump, it was well over $1000. Piston pumps were well
known 50 years ago, and can last a century if taken care of. We have
replaced the rubbers and packing in a few of the old ones, but parts are
getting hard to find. We now have the same pump available that the solar
force is built on, brand new, and can easily get replacement gaskets and
packing, for less than half the price that Conergy (formerly Dankoff) is
selling the Solar Force. You can hand crank, pedal, or install a ac or
dc motor to this pump. 300-400 rpm is recommended.
Jim Juczak of Woodhenge.org has finished his book, The High Art of Scrounging, and his DIY Hand Powered Deep Well Pump. See http://www.woodhenge.org for details.