zarin saidI put tap water INTO water bottles so that I drink enough water. Works well for me.
You REALLY shouldn't do this, a friend who had cancer was told by her oncologists to never refill plastic bottles of water because of a high level of carcinogens apparently
There are only 3 types of plastic that this is true for. The bad numbers are 3, 6, and 7. If you have a bottle with one of these numbers on the bottom, do not reuse it.
1, 2, 4 and 5 are the safe numbers.
Just make sure your bottle is cleaned properly before reusing it.