My wife and I have noticed that when we turn on the water (hot or cold) in the sink in one of our bathrooms, after a few moments we notice a mineral/earthy type odor. It doesn't smell like sewer/sulfur or anything of that nature, instead it almost has a metallic odor - hence the use of "mineral" in the description.
We do not notice this odor from the shower/bath in the same bathroom, nor the kitchen, nor the 2nd bathrooms sink or shower.
Any clue what it could be? Would this be something from the pipes?