What causes the foul 'rotten egg' smell in my water and what can be done about it?
Naturally occurring bacteria in water use sulfur compounds and sulfates from decaying plants to convert organic substances into energy. Hydrogen sulfide gas is formed as a by-product and becomes trapped in water underground, sometimes leaching into private wells. When it is allowed to escape by opening a faucet inside the house, its presence is immediately evident by that annoying ‘rotten egg’ odor. Extremely high concentrations of hydrogen sulfide in the air can be toxic, but when it is present in a well, the levels are typically nowhere near toxic and are mostly just a nuisance.
It tends to cause foul taste and odor within the well water and does not cause health problems. It can, however, be very corrosive to metals such as the copper pipes or stainless steel sinks in your home. It can also react with the resin in your water softener, producing a black slime.
Because hydrogen sulfide escapes quickly from water and may be gone by the time the water reaches a laboratory, it is best to perform an on-site test.
If a smell very similar to hydrogen sulfide is only in hot water, the water heater anode may be causing the problem. The magnesium corrosion control rod (anode rod) inside the water heater releases small amounts of magnesium as well as hydrogen, which can combine to form hydrogen sulfide. Replacing the rod with an aluminum one may reduce the problem.
If there is hydrogen sulfide contamination within the well, BOTH hot and cold water will smell foul. Treatment varies in relation to source and severity as well as the pH level of the water. In most instances, hydrogen sulfide can be removed through a chemical-free method called aeration. Other forms of treatment may include chlorination or mineral/media based filtration using chemical regeneration. Heine Plumbing has been treating this type of problem successfully for years.