RVs have three holding tanks for water: freshwater, graywater, and black water. If you have a rotten egg smell coming from your taps, it’s from your freshwater tanks. Most of the time this occurs after you’ve had your RV stored away for some time.
The rotten egg smell coming from your water is usually due to hydrogen sulfide gas and sulfur microbes in the tanks. The hydrogen sulfide gas produces a strong, unpleasant odor and taste. If the rotten egg smell is in the hot water, it could be contributed to metals in your water heater reacting with the water.

Types of Sulphur Found in Water
Across the United States, the drinking water contains more than 300 chemicals. Many people complain about strange odors coming form their taps, especially if the water supply comes from a holding tank. As we mentioned, sulfur is the cause for the rotten egg smell.
Sulfate is the result of sulfur and oxygen combining. Sulfates are naturally occurring in soil and rocks. Over time, sulfates are released into the water. On the other hand, hydrogen sulfide is the result of the decomposition of organic matter. These bacteria change the natural sulfates in water to hydrogen sulfide. Bacteria that is sulfur-based thrives in the oxygen-deprived water in tanks/wells.
When the concentration of hydrogen sulfides is elevated, it can have an effect on the smell and taste of water. The sulfates don’t have a smell but do leave behind a build-up in the water that can make it taste bad.
Hydrogen sulfide in the water can cause damage to pipes as it destroys a variety of metals, leaving stains on silverware and plumbing fixtures.
Getting Rid of Hydrogen Sulfide in the Water of Your RV
For most people, the rotten egg smell is not only bothersome, but also embarrassing when visitors come by. Therefore, you want to get rid of it as quickly as possible- but how?
The very first ting to do is determine the source of the smell. If you open your faucets and the water smells bad, the problem is in the freshwater tank.

Pay close attention to where the smell is originating. You may need to clean all of your holding tanks. In some cases, your graywater or black water tanks may be releasing odors, especially if they’re close to full and haven’t been cleaned in a while.
Next, you need to open the taps for five minutes to get rid of the sulfate clog that is causing the smell. If this doesn’t help, you’ll want to bring in peroxide. Experts recommend that you leave your tank half-empty and add about 20 ounces of peroxide to the water and allow to sit for 3 hours. Then, dump the water.
You also need to do the same thing for your water heater. After you do this, you’ll want to make sure that you clean your holding tank thoroughly because, if hydrogen peroxide is swallowed, it can be harmful. If you prefer, you can use white vinegar instead of hydrogen peroxide.
Conclusion
If the water coming out of your taps smells and tastes like rotten eggs, you need to clean out your freshwater tanks. You need to take the time to clean out your tanks from time to time and always drain and clean before you store for the winter.