300 feet is not extreme in San Diego County, Eugene. In your area there are a few high water tables, but these are fairly exceptional over the larger geographical plot of groundwater. Some other areas of the state and country you can drive a pipe with a jack hammer or whatever and get water. They have true shallow aquifers,most regional ground water is in deep fractured granite. The only way to get it is to go down deep. Just a rough estimate, but the average well I have seen in reviewing the files at the county, is deeper than mine.Now, as rural lots farther away from streams start to get developed, on hilltops and such, some people are drilling 5 or more times the depth of mine. I have been to a houses where the well gave a trickle at 1800′ feet and have heard of deeper.neighboring wells will vary greatly in depth and output. Of two neighbors one got a trickle at 800 feet and another got 225gpm at 300 feet( she had no water until she hit this).
The ground water, besides being deep, is also often of low volume potential. My area is zone restricted for groundwater at 5 acres per dwelling unit and the resource would probably drop significantly at that density.
The well drilling rig typically used in this area is not something I would not mess with even if it could be rented. It is very heavy duty and has too many dangerous moving parts to go at it without some serious OJT.
