sulfur smell in bath sink

My bathroom sink has a frequent but not constant smell of sulfur in the water. The toilet and shower come off of the same line, but they never smell. I am 100% positive that it is not from the drain, I have filled a glass with the water and you can smell it in the water outside of the bathroom. I am on a community well, but none of my neighbors have had any problems. The only advice I got that seemed plausible was that you can still buy leaded solder, and that someone may have redone the supply lines using it. When some mineral in the water mixed with that bit of lead it could create a smell. I don't know if this is possible or not, plumbing is not my strong suit, so any advice would be greatly appreciated!

Hi fyaym, welcome to the forum

As you say that the water of the shower and the toilets come of off the same line I am more inclined to think the problem could be at your tap system. Have you changed that lately or checked?

Thanks for the welcome

The faucet was new, I put it in soon after we bought the house, so I am not sure if the problem existed with the old one since it isn't constant. I did just check the pipes in the basement, and after pulling off some of the pipe insulation I saw something kind of strange. In between the T off the main line and the next elbow, there was a two inch piece of red rubber with a ring clamp on each end. I assume that isn't acceptable but I don't know if it could cause the problem. Right now I am renovating the bathroom and everything is pulled out so I can't try a different faucet, I wanted to fix the problem while everything was still open and easy to get to.

What is important to know is if that red rubber and its ring clamp also is on the pipe that supplies water for your toilet and shower. If it is only on the pipe leading to your sink where this problem exists I would suggest you replace this red rubber band and its clamp to plastic.

It is very important to notice if cold water smells like sulphur. If it does not, it is your annode rod in your water heater. As the annode rod ages, it creates hydrogen sulphoxide. It's just that it's more noticeable in a lav sink than anywhere else. I won't go into the reasons why this is. If your cold water does smell, it is very possible that there is a section of threaded galvanized steel pipe on that particular branch. Maybe even inside the wall. Believe it or not, if the company or person who cut and threaded that section used sulphur-lard based cutting oil the smell will never leave and actually impregnates the rubber and plastic parts of any faucet. Find the offending galvanized section and replace with approved water piping, copper or plastic, or replace your annode rod and drain and flush your water heater.

G-r-e-a-t, I hope fyaym will read this soon, thank you askaplumber1st.

Since the water is not the source, it is the drain. I had a similar problem. It was the overflow drain. It did not have a way to completely empty into the drain because the hole in the drain pipe was higher than the sink's overflow tube. Water that had collected there was stagnant and stinky.
Pour some disinfectant down the overflow for a quick fix. You can use various things, but don't use anything too caustic. If this is the problem, the caustic chemical will stay there for a long time, and could case damage to the drain pipe. Dilute bleach would work, or even hydrogen peroxide. For a better fix, you will have to remove the drain pipe and modify it to match the overflow pipe.

the hole in the drain pipe was higher than the sink's overflow tube

another little detail to pay attention to. thank you so much for mentioning this