I was going to post this in the main permaculture subforum, but since I'm a new user I suspect someone would think it's a lame attempt at real estate spam. I swear it isn't! Just curious! I wish I could afford an acre or more of land.
I used to live in Northridge, and have taught several various climbing, winter camping, backpacking and other outdoors classes around Mt Pinos/Frazier Park. At one point in ~2006 I even scouted real estate, and like everything at that time it was ridiculously overpriced due to rampant speculation and development (mostly further S along the Grapevine). While studying geology my Seismology class took a fieldtrip to Frazier Park area to see the trenches that have been cut across historically active fault scarps, along one strand of the San Andreas Fault . Once you make that connection and realize all those dramatic, triangular-shaped steep hillsides reflect seismically active zones...you tend to look elsewhere for land.
I doubt there's water. This area's a weird blend of singlewides and upscale vacation cabins and ranches, the dirt-poor living besides the super rich. It's a 1.5~3 hr commute to the San Fernando Valley and I hear traffic's now far worse. I'd be looking further back in the hills, maybe following the 33 S towards Ojai: use googleearth to scan for green strips running perpendicular to the topography to identify wet areas. AVOID green strips running parallel to contours, close to the base of any slope: fault scarps act as conduits for upwardly moving groundwater. Building atop a fault is just a really bad idea.