Sorry if I wasn't clear before, I was speaking from experience on wells in Colorado (my father has a well in Washington state- he's got like 6-8' to water)
a quick search found this:
http://www.simplepump.com/OUR-PUMPS/Flow.html
you can check the water table level with a small weight, fishing bobber & enough fishing line to reach the water (line will go slack when it hits water)
A generator, or a DC-powered pump & solar array (and batteries) would also keep you in water during an outage... during some nasty winter storms, I've been without power for more than 3 days- gotta have something as a backup