Scott - How much you end up carrying will depend on a bunch of factors. Here are just a few:
(1) How ‘wet’ or ‘dry’ & ‘hot’ California is the year you hike.
(2) How much you sweat on any given day. (keeping cool is key)
(3) How ‘fit’ you are: the better shape your in, the less water you will need.
(4) How good your water source info is. (But even with ‘good’ info, you might be unpleasantly surprised at times… so you can never totally rely on water cache info)
In '97 I carried more than 2 liters only once: the area near near Kelso Valley Road (Data Book mile 616). This was before a trail angel named Mary started putting caches through this section.
In '05 I never carried more than 1 liter. '05 was an exceptionally wet year for SoCal (an alltime record south of L.A.) and there was quite a bit of water even in the ‘desert’ sections. Billy Goat counted 17 water sources between Campo and Lake Morena just before the Kickoff!
I hate carrying water since its obviously so heavy. And I know my ‘comfort limits’ - I can comfortably walk 10 miles on a liter of water in the desert in hot conditions. When I ‘camel up’ at a water source, I normally don’t need to dip into my 1 liter reserve until I have walked around 10 miles. This gives me a 20 mile range on 1 liter (comfortably - of course I could go much further if I had to). In '05 I didn’t run into a single gap that was greater than 20 miles.
Of course I was gambling with this strategy (not with safety, but rather comfort) In '05 the gamble paid off - I didn’t lug around extra pounds in my pack.
In '97 I got burned once - a listed spring had been recently vandalized (blown up with dynamite). I ended up walking in 90 degree heat much of a day & spending that night without water… Not at all pleasant, but I was physically fine & I’ll never forget how wonderful the cold spring water tasted when I finally found water the following afternoon.
In Ray Jardine’s PCT Handbook (before he wrote “Beyond Backpacking”) he had a chapter called “The Psychology of Thirst.” In this chapter he mentioned some incredible examples of individuals (like the French Legion) crossing hard core desert regions (Sahara, etc.- over one hundred miles) without water.
You’ll eventually find what’s the ‘right’ amount for you personally. I certainly wouldn’t recommend carrying just one liter - I did this in an exceptionally wet year & I know how much water I generally need from former experiences.
As you gain experience in the desert, you’ll figure out what’s the best amount to carry for any given mileage & temp.
Some hikers find that carrying extra water in their hand in a water bag alleviates the burden of carrying the extra weight on their back.
Here’s the current PCT water info for SoCal (updated frequently):
www.4jeffrey.net/pct/a.htm
Have a great hike!
freebird