Sulfur (Rotten Egg)
You would know it if you had this problem! A frequent cause of musty, earthy odors in water is naturally occurring organic compounds derived from the decay of plant material in lakes and reservoirs. In some parts of the country, drinking water can contain the chemical hydrogen sulfide gas, which smells just like rotten eggs.
Sulfur smells can occur when water comes into contact with organic matter or with some minerals, such as pyrite. The situation mostly occurs as groundwater filters through organic material or rocks. A few tenths of a milligram of hydrogen sulfide per liter can cause drinking water to have a rotten-egg odor.
Water containing hydrogen sulfide can have an odor that is objectionable (and the water may taste really bad), but generally the water is not harmful to health.
Water treatment can improve sulfur smell issues.
In most cases, sulfur smell is a noticeable issue in bath water and at the faucet(s) where water is used for drinking. Since hydrogen sulfide is a gas, testing by your Vesta dealer must be conducted at the site.