rotten egg smell. to me here in united states = liquid propane gas leakage. they add a chemical to the gas for heaters. and if you get a gas leak, you could possibly smell rotten egg smell.
if not a gas leak, i would suspect, sewage leak. ya have normal drain in bottom of sink, and if bathroom sink normally an overflow in the sink. i have seen some rare sinks were overflow and bottom drain on sink required you to TEE the 2 areas together before going into the P trap. and then having enough water in the P trap to fill the P trap to keep gasses from exiting out of the bottom drain or overflow...
i have seen it were just running enough water has caused the "vents" on the sewage line, cause a back draft per say. which allowed gases from the sewage line to push back through the P trap and back into the home.he water heater and sink down to the bottom before next use. over time, this crud begins building up in the bottom of the hot water tank.
a simple flushing of the hot water tank with some sort of chemical say bleach or like. can disinfect and help remove the crud in the bottom of the tak and flushing it out with some chemicals, does not really clean it.
this goes with old pipes in the house as well. more so with wells with heavy metals in thups.
so my question is how bad is your water heater, and how bad are your pipes with crud build up?
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WOW!!! Thanks boggen for the complete reply. I believe you must be a good and helpful neighbor, and not afraid to take time to help others.. You covered problem. bobmisi was first poster and on the money. deer fan was on top of it too. And you covered every problem in water universe. And so do all the posters help each other. It's great.
The problem, 99% sure. I eliminated drain because cold water could run and run, no smell. I turn hot on and wait for cold to change to hot. Hot comes out for about 15 seconds and the smell starts. Coincidently I changed the spigot set just before then. The sink wasn't used much for a time while waiting for time to change, the hot side was off. I have another sink close by so I very seldom used the now smelly sink. What I now think is the trap has a colony of mold or some other growth causing oder. Reason I rejected the drain theory is because cold didn't make smell emit from drain. The hot loosened or aggravated mold to klick loose the smell and cause it to go up into sink, causing me to be sure it must be just hot water.
Why I think I'm right.. I'll post answer later. Have to log now.