All it takes is ONE TIME.... of running out of water, and you'll never bitch about carrying around "too much" water EVER again!
When I was very green and just barely started getting into hunting in 2014... I ran out of water when I'd descended down Mt Wilson and further descended past Newcomb Pass and went down to Devore... then I realized I needed to turn around and go back the way I came. At Newcomb Pass, my 3L bladder ran out on that hot and muggy October mid-80's afternoon, down there at the base of Mt Wilson it's 3.5mi to get up to the top! something like 2700ft in Elevation Gain! It was about 3:30p
In my pack I had a nice big Orange and a big Apple. I was SOO thankful for them!
So I stopped, relaxed and proceeded to eat them both at a calm pace... and thought about what lied ahead.
Told myself, "Welp, you know what you gotta do. You're just gonna have to go super slow and take a lot of breaks, and take however long it takes to get out of here."
This was "The Rim Trail", which is like this brutal seemingly endless series of switchbacks that will eventually get you back up to where the observatory is.
By the time I got close to the top... the entirety of my tongue was COMPLETELY bone-dry to the touch... as far down into my mouth as I could touch with my fingers. As well as the entire inside of my mouth.
The inside of my clothing was sopping wet with sweat. It was a constant battle with heart palpitations on those switch backs as my body was beginning to steal water from my blood stream, thus lower it's volume, thus the pump needing to pump more and faster! So at each turn-around in the switch backs I had to sit or lean-up against something to take weight of the pack off and let my heart calm back down a bit before proceeding again.
I was soo out of it I kept saying to myself "Daddies comin' Papa!" (term of endearment I call my Boy), and with the way that terrain is, I was nervy as hell about a MtnLion seeing me coming along all huffing and puffing and out of it. Would be EASY for them to pounce down upon ya from the many pieces of rock and brush adorning that trails hillsides. So I kept repeating to myself over and over "Thumb forward (to disengage the tang safety on rifle), jam it in his guts, pull the trigger" because I was soo beyond exhausted I didn't want to ditz-out if something bad went down. So I kept repeating that to myself so those thoughts were fresh in my mind constantly.
I am VERY lucky that the temp dropped down to 45F by the time I got up to the top at about 9:30p. Not sure I could have made that much of a climb without water otherwise.
As I approached the top... I thought to myself there's got to be a water tap up there with the observatory and those various building they have. Guess what? It had one of those freakin' keyed spigot handles on it! I've never been soo pissed at humanity in my life! But then I figured they probably needed to do that so Bears wouldn't turn on the spigot I suppose.
Once I got to the top.... my vehicle was still probably like... 900yds away but it might as well have been miles with how physically exhausted of a state I was in.
Then a bit of luck happened! As I limped past this on-site housing building, I happened to be lucky enough to hear the squeal of a toddler! Being a father myself, I knew that meant an adult had to be there too!
So I got closer to the house (while maintaining a respectful distance from it) and shouted "Helloooo!!!! Anybody?? I need Help!!!! Please!!! Anybody?? I need Help!!! I ran out of Water at the Bottom of the Mountain!"
A lady opens the door of the place, at which point I get soo humbled and say to her "I am soo sorry Ma'am... please forgive me... I know it's the middle of the night, in the middle of the Forest... but I ran out of water down at the bottom of the Mountain... do you have any water?"
She lets me know she'll have to contact her husband to come over, to which I state "I completely understand Ma'am." as she then directs me to their lil patio table and chairs. So I proceed to drop the pack and rifle on it and crash with my torso and head laying upon the table.
I'm sure I'm glossing over the back-and-forth of the conversation there a lil bit. But anyhoo... after she called to her husband on the phone inside the home... like an angel she brings me several bottles of water which I proceed to squeeze the bottle to force-feed into my pie-hole as fast as humanly possible!
Eventually the guy comes up with his work truck. He explains to me that he'll have to take the rifle, to which I reply "I totally understand man, it's your family, it's the middle of the night, I totally get it" I explain roughly where my vehicle is at.
Then he backs up the truck and allows me to rest upon the tailgate/bed... and he drives me over to my vehicle while I'm laying on my back looking up at the stars.
Not only that... he was a real stand-up guy for the fact that he waited until he made sure I was in the car and the engine successfully started and I was on my way, before he returned to his family and job.
WHAT DID I LEARN? : When it's a new location or a new trail for you? Make sure you divide up your water in half amongst at least two main containers... so that way if you're sucking on the tube a little too much and blow thru half your water.... you know right then and there to STOP!!!.... and NOT proceed anymore further away from your vehicle. And to turn around.
Having such an experience will make you NEVER EVER EVER take water for granted EVER again! Now within my home I have a substantial amount of drinking water cache that I ALWAYS keep topping back up with each visit to grocery store. Approx 15gals for the 3 of us. I'm not as concerned about running out of water at my home, cause we have a pool and I figure worst case scenario of earthquake and waterlines break for awhile, I can boil the pool water if I had to. If we didn't have a pool? I'd probably make room for an even larger cache of water in the garage.