8 e0 g2 K! x4 f7 a1 ]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. ; q: ^/ ^* s: r4 K' Q # o q) E4 R9 j# {& v! bBeside,furnace hot water coil is made of metal. Some of it will come into the hot water.