For a lot of us #n00b thruhikers water was a huge talking point at the start. How many liters do we carry? Where is the next water source? How much water do others use up? Technology these days makes things a little easier though- the trail has a well documented online list of water sources called the PCT water report with regular updates from hikers as they pass those sources.
The other saviors are once again the trail angels. Like here at Mile 91. There is no water on the trail between Miles 77 and 105, which is a long way for most of us especially at the start. So some trail angels along with the @pctassociation maintain this huge water cache. I’ve heard they have to use offroad vehicles to lug the gallon bottles over there. Most of the path to there is littered with hikers hiding in the shade of bushes dehydrated and very grateful.