I have resources in sanctuary, didn't know about the water bit though.
That might be a solution for health.. water heals a bit.
I've got a ton of weapons and armor and crap I was going to sell but there's only so much I can sell to one person before their caps are gone.
Pretty sure it was the same way in the other games but I just haven't come across that many people yet.
I think carla and the farmer settlement might be the only people I can trade with, I did just ally with the robots but I've got a TON of crap haha.