smelly water

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1003KB, 2320x3156px

This bathroom sink hasn't been used much in the past few years, and the water seems to have developed a light musty smell.

I thought the smell was coming from the main drain or overflow, but after bombing them with vinegar and baking soda, I realized the smell was washing off onto my hands and lingering. I did a taste comparison, and the bathroom water tastes slightly inferior to the kitchen water, which tastes very clean. The house uses city water btw.

I replaced the faucet and the water supply hose, but I can still smell something on my hands. I get the feeling that something has grown in the pipes leading to this bathroom, but beyond this I don't know what to do. I'm no plumber, and the pipes are tucked away and physically out of reach; would rather not mess with them anyway.