illevor said:
A Swedish man I met along the way maintained that carrying more than 1 litre was pointless.
This is so devoid of specifics as to be meaningless. What time of the year are we talking about? Were the fonts operating? What was his build? Was he simply justifying that he was only carrying a litre of water himself? Was this working for him, and he was well hydrated?
Is the fact that he was Swedish important? Walking in Sweden, even in summer, is unlikely to be the same as walking in Spain at the same time of year. I recently walked in Norway, and could have collected water every half hour or so, should I have wanted to do that, for most of St Olav's Way. I certainly could not have done that on the
Camino Frances. Leave aside that when I walked in Norway, daytime temperatures didn't reach 20 deg C, compared to days above 30 deg C when I was on the CF.
In Spain the towns and villages were closer together, along with the opportunity to use a font, visit a bar, or just ask at a house if that were required. If all these things work, you might be able to obtain water every hour or so, but it relies on everything working. Carrying as little as one litre might be okay, but I would personally prefer to have a buffer against something untoward happening.
All that said, one is unlikely to reach the point where lack of water is life-threatening on the CF. What is at risk is that without regular and sufficient water consumption, you will become increasingly dehydrated over the course of the day and begin to experience some of the less pleasant signs and symptoms of that. If it is hot, and you continue to exert yourself, you might also begin to suffer from a heat illness - although I understand older people tend to stop short of actually suffering from heat stroke.