You'll find three campsites on the way up this trail: The first one has plenty of water, but it's WAY too close to the trailhead to camp. The second one is usually (always?) bone dry, unless you have "must-build-an-ark" kind of weather. The third one, where you'll want to camp, has plenty of water and plenty of campsites.
As you enter this campsite, you'll see a GREAT-looking spot located just to the right of the trail about 150 yards BEFORE the campsite proper. If you stop there, a ranger will kick you out. It's way too close to the water-- but a nice spot to kick back once you have your camp set.
By the way, by far the steepest part of the trail is the first mile or so. Have fun.