: I once lived in a house where similar things happened. The cold taps at multiple locations seemed warm sometimes. Finally when hot water came out of the outside hosebib I took a closer look. It turned out that the public water came in the house at about 120psi and the person who did the plumbing (very possibly not a plumber) put a pressure reduction valve on the line after the split to the water heater. So only the cold line was at a low pressure and the hot water backfilled the cold lines due to this pressure difference. It's a longshot, but take a look at your plumbing in this regard.

:::Thanks. It was worth a shot but doesn't appear to be the case. Although, maybe the tank's PSI could cause backfilling? I'll look into it.