When I posted earlier in this thread, I avoided the issue of how much water to carry, in part because the OP was proposing to carry a little over 2 li in a combination of a bladder and bottle. There have since been several posts recommending carrying only 500 ml, some based on the poster's personal experience while in others it isn't clear. Members should think very carefully about that and whether carrying so little water will be safe.
My personal experience on both the camino and many years bushwalking in Australia is that following this advice would result in a substantial fluid deficit over any individual walk between places with potable water. I have measured my fluid consumption walking on a warm spring day walking on bush tracks on training walks in undulating terrain here in Canberra. It was 700 ml / hr. While I can tolerate a small fluid deficit over a short walk, if I don't have a plan to collect and treat water on longer walks, I know that I risk heat stroke, and its precursor, heat exhaustion. Having come close at least once, I have no desire to do that again.
This year I walked the Caminho do Tejo and the the CP, starting in late Apr walking through to early Jun - late spring and early summer. There were some quite hot days leaving Lisbon, and it was generally hot all the way to Porto. I was regularly drinking 3 li of water from my bladder during the walking day, with many days drinking more. That was normally supplemented by a can of cold drink and coffee wherever I stopped for a snack or meal. I preferred ice tea, but if that wasn't available, I would have a soft drink instead. That would have amounted to well over another litre of fluid intake.
When I got to where I was staying, I would normally mix about 500 ml of rehydration solution and drink that while doing my domestic chores, and there would then be other refreshments over the course of the evening in the albergue and over a meal. Even with all this intake, my urine colour stayed obstinately darker than I would have liked, indicating that I was still dehydrated.
While the CF generally has places with potable water within an hour - I once researched this and about 60% of the time that is so - on a warm day, only carrying a 500 ml bottle would still risk a fluid deficit which would be difficult to make up during the day. As for
@Rick M's suggestion that 500 ml would suffice for 14 km (over three hours walking for me as I get older), it would be positively dangerous for me to attempt that, even on the mildest of days.
At the time
@Mikey - camino plans to walk, in Mar next year, my experience walking in late Mar to early May was that there were fonts that had still not been turned on for the summer. I don't know whether this was a common practice, and I was carrying enough anyhow so that wasn't a big issue. It did mean that I checked my water more consistently when I stopped for a coffee and snack, and topped it up if that was needed for the next leg of walking.
How you carry your water is very much a personal preference. I have said all I need to say in my earlier post (#11). How much you carry is more important, and with a bit of trial and hopefully not too much error, you can work out what your consumption rate is. What I do recommend is that you start this process carrying at least a litre of water.