San Gorgonio water availability is a big problem now because let's face it...this winter sucked and there ain't no snow melting. I hiked out of South Fork and hauled 5 liters with me. Good thing, there wasn't a drop to be had anywhere. I understand the same is the case on San Jacinto now too. I don't know how much later this summer you're talking about, but for now water on the main trail is not a problem. I used my water filter whenever I filled up and that worked great. I used the small lake at Trail Camp since I camped there, or Consultation lake which is nearby and much bigger would have been an option too. Both of these sources are at 12,000 feet. There are several options lower than that as well, and the one I used was the creek at Outpost Camp which you cross anyway. It was flowing heavily last weekend. You could also use Mirror Lake, or many spots along the creek leading up to Trail Camp, such as at Trailside Meadow. Basically you can (and should) drink to your heart's content. There's plenty of water.
