' }8 R0 g3 s4 Q8 r+ E# nHot 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/ C s) D0 M) p8 L9 c) Z: ?2 P6 ^, w: g1 J2 K) f
Beside,furnace hot water coil is made of metal. Some of it will come into the hot water.