On OV I boil the tap water in the kettle, put in jug in fridg to chill before drinking, have done this for the last few OV cruises, after it cost me £70.00 for water over 3 week holiday and have had no problems.
Strange question. Water from the ice bucket or the tap or in a bottle....yes
Any other water in cabins I would treat with caution. .....
Drink water from tap and use it to make tea.