In reply to phja:
The huts will provide blankets etc normally - just take a liner with you.
Most alpine huts I've been to will charge you for water (horrendously!!!) Covers the cost of either having water shipped in, or purifying / filtering the stuff they can pipe in naturally. Plus a good dollop of profit.....
normally there is unfiltered, untreated water in the toilets etc - you can drink this and take your chances as an alternative.
Other possibility is (if your above the snow line and there's somewhere safe that you can collect it from) is to take a light stove and melt snow.
You'll not make any friends with the custodians by dodging buying their water though!!
Cheers,
Stuart