Hydrogen sulfide is a naturally-occurring gas that causes an odor that can be described as anything from rotten eggs to that of tidal flats at low tide. At high concentrations, it will oxidize in the water when it is released from a faucet and will cause a black stain.

Iron will cause an orange stain and many times it will be accompanied by manganese and hydrogen sulfide gas odor. Iron staining will be chocolate brown when it is combined with manganese.

Uranium treatment for the private homeowner will be necessary if the concentration of uranium is above EPA’s maximum exposure level (MCL). The EPA has set the MCL for uranium at 30ug/L (ppb). Although uranium is radioactive, the MCL was set based on its chemical toxicity. At elevated concentrations, uranium affects kidney function and can cause cancer.

Manganese will cause a black stain and is often accompanied by iron staining and hydrogen sulfide (egg) odor. In combination with iron, manganese staining will sometimes be chocolate colored or brown.