I have noticed that when I have stayed in any hotel that if they have a plastic kettle in the bedrooms the tea and coffee tastes disgusting. So if your replacing your kettle at home try a stainless steel one instead.The taste is more to do with plastic having a lower melting point.
Very occasionally I can taste whatever chemical it is they add to water to keep it clean (chlorine?) but I just fill a big jug, cover it with a tea-towel and the taste seems to dissipate. The water tastes lovely and sweet after a while.
I always take a sipper bottle of water to bed and drink that before I sleep, when I wake (in the night and at 6am) and I let that stand with its top off too. Otherwise I get the slightly bleachy taste.
All this is leading up to the speculation that maybe hotels have to add something extra to their water storage tanks? Is this why it makes beverages taste grim?