Interesting.
Ayurveda suggests putting water in a copper cup at night and drinking it in the morning to clean you out. However we consume water from copper pipes which essentially does the same thing except that all the water is affected not just that one cup.
Maybe that is why AV suggests not drinking water.
Of course drinking water that has been heated in the presence of copper is a bad idea as this makes it toxic. Since most people have tea with water that is heated with some sort of copper element and since most water heaters use a copper element, it can be a bad idea to drink that water. I suspect most people are not aware of this and it may well be that the elements have been coated with some other metal, but then due to the extreme heat and constant water contact the elements will corrode and the coating dissolve. Also the coating may have weird properties.
