I'm having a well put in in the foothills just east of the Sierran Nevada mountains. The area is rocky (decomposed granite) and other homeowners in the area have wells ranging from 150 to about 300 feet with good flow rates. One neighbor just put in a well (same driller) and gets 20 gal/minute. My well digger went down to 390 feet without finding any significant water, but he thought there might be some higher up based on the hole filling overnight. So he removed the "mud" from the hole but found only about 7 gal/minute (which seems inadequate for a 3700 sq ft house). He says the only other (than 7 gal/minute) option at this point would be to go deeper. This would be deeper than any of my neighbors, most of whom are at slightly higher elevations than me.
My questions:
1) Would it make sense to drill elsewhere on my 2 acre lot? It seems like perhaps the water table varies since my neighbors have good wells. Starting over is an expensive proposition but may be the only option if water isn't found deeper.2) What other choices are there if more water is not found in the present hole. Can large storage tanks be used to "buffer" the inadequate flow?
3) What is a minimum reasonable flow rate? We'd hoped to use a new variable speed pump that can handle up to 30 gal/minute.Serious advice is welcome.