* t( Q0 M+ [% b% k! l. G0 DHot water has went through all your home's internal pipes whereas cold water comes "direct" from your local reservoir. Which should be pretty safe." e4 X7 e* O1 e" d7 J, O0 Y C
; Q o4 N a) S) vBeside,furnace hot water coil is made of metal. Some of it will come into the hot water.