I'm sure I read somewhere that the optimum temperature for making tea is 98ºC. The water from those hot tap things is fine for the purpose, IME. Just don't do the American trick of serving a cup of warm water with a teabag on the side.
I have had that American liquid they describe as tea. It was awful.
Strictly speaking, we are segueing into the realms of tea nerdery. Your standard British cuppa (largely an Assam blend) should be made with boiling water for full flavour extraction, but the full boil is really aimed at loose leaf tea, and not the dust that passes for proper tea in supermarket loose leaf tea boxes (I'm not even all that keen on Twinings). Once you start considering white and green teas, herbals, pu-erh and the like, it becomes more complicated.
The UK Tea and Infusions Associations specifies 90-98 degrees for black tea, but they don't differentiate between large loose leaf, shredded loose leaf, or tea bags, so frankly I don't think they are to be trusted.
Sam