one faucet smells

[MainerBob]

We are on city water here in Bismarck. Each time we open the faucet at the lav sink there is a sulfur smell and bad taste. Left to run a few seconds it clears up. Next time same thing. It only needs to sit a few minutes to "resmell." We just use a cup of water from the kitchen to rinse teeth, etc. That faucet is the only one this happens to. We've checked the shower and kitchen. No smell or taste. This has happened in other locations as well so it isn't the fine Bismarck water supply. Any ideas? I don't really want to "sanitize" the whole system if I don't have to.

[Old-Biscuit]

IS there a 'washer' prep and/or outdoor shower set up in the same area of bathroom.

Stagnant water line(s) can go sour and then affect water in nearest flowing outlet.

[GaPete]

My problem turned out to be deposits in the hot water tank. Is it more prevalent from hot side?
I bought one of those tank flushing wands from Camping World and thoroughly flushed my tank. No more smell.