& Q( G( e- C8 U* c1 V- A$ j! @0 ~' }Hot water has went through all your home's internal pipes whereas cold water comes "direct" from your local reservoir. Which should be pretty safe., V( E1 U$ [/ f
( w" B' P8 e$ H4 ~3 |6 dBeside,furnace hot water coil is made of metal. Some of it will come into the hot water.