I hiked Olancha in late June so will try to answer. For my hike, there was no water until around the route flattens out at around 9200'. Hiking through the meadows to around 10k there was sporadic water and a running stream. The top section off the PCT (from 10.5k to summit) has no water at all.
I hiked with my usual set up consisting of 100oz of water in a camelbak and two 32 oz bottles of gatorade and finished with a few ounces left. I didn't refill with spring water on the hike.