Or is there another reason why hot is usually on the left?

Adam
The explanation I had from my grandfather some 50 years ago was:

a. people used to have just one tap - for cold water - which was on
the right as most people are right-handed;
b. when this new-fangled running hot water came along (from, for
example, the gas geyser) the tap for that was added to the left; and
c. so a convention (of sorts) was born.

Should I put this on Wikipedia so it must be true?

By the way, in our house they are the other way around. On the other
hand, as we do not have any water tanks in the loft you could at least
be confident of not drinking an infusion of drowned rat.

--
Robin