Wow yeah no offense to anyone who plays games RAW, it's my default preference in general, but yeah I'm nerfing that. 11 days worth of adventurers water would weigh like 100lbs, especially in summer. Getting ready to start up a miniseries campaign before diving in deep, but the survival aspects of FL are what most appeals to me about the system. I'm probably gonna cap Water at D8. I understand that will impact talent and action economy and the like so I'll have to see what kind of damage that does, but if as you say your players haven't foraged for water in ~30 sessions I feel like I'm not at that much risk for breaking things too terribly.
I wonder if it might be an unplaned leftover from the alpha, where water and food was required to be able to heal damage, rather than just resting. We played for that for a long while, and that sure eats up (pun intended) the resources pretty fast.
If I wanted to run a game with focus on resource management and survival, I'd probably consider removing the resource dice all together, and keep track of actual days worth of food and water instead.