Hydrogen Sulfide (Sulfur) and Sulfur Bacteria in Well Water
Hydrogen Sulfide (Sulfur) gas (H2S) can occur in wells anywhere and gives the water a characteristic “rotten egg” taste or odor. Hydrogen Sulfide (Sulfur) gas results from different sources. It can occur naturally in groundwater. It can be produced by certain “sulfur bacteria” in the groundwater, in the well, or in the water distribution system. It can also be produced by sulfur bacteria or chemical reactions inside water heaters. In rare instances, it can result from pollution.
In most cases, the rotten egg smell does not relate to the sanitary quality of the water. However, in rare instances the gas may result from sewage or other pollution. It is a good idea to have the well tested for the standard sanitary tests of coliform bacteria and nitrate. Sulfur bacteria are not harmful, but Hydrogen Sulfide (Sulfur) gas in the air can be hazardous at high levels. It is important to take steps to remove the gas from the water with an aerator or even a sulfur eliminator that can remove up to 20ppm of sulfur. You can also vent the gas to the atmosphere so that it will not collect in low-lying spaces, such as well pits, basements or enclosed spaces. Only qualified people who have received special training and use proper safety procedures should enter a well pit or other enclosed space where Hydrogen Sulfide (Sulfur) gas may be present.
The odor of Hydrogen Sulfide (Sulfur) gas can be detected in water at a very low level. Smell the water coming out of the hot and cold water faucets. Turn the water on all the way cold and wait 90 seconds, then smell the water. Do the same to the hot. If the smell is coming from both the hot and cold water, then it may be your pipes or your water system causing the smell. It could also be your faucet screens. You also may want to check which faucets have the odor. If only certain faucets have the smell then it could be the faucet or faucet screen. The “rotten egg” smell will often be more noticeable from the hot water because more of the gas is vaporized. Your sense of smell becomes dulled quickly, so the best time to check is after you have been away from your home for a few hours. You can also have the water tested for Hydrogen Sulfide (Sulfur), sulfate, sulfur bacteria, and iron bacteria at an environmental testing laboratory. The cost of testing for Hydrogen Sulfide (Sulfur) ranges from $20 to $50 depending on the type of test.
If the smell is only from the hot water faucet, the problem is likely to be in the water heater, either the hot water tank itself or the hot water pipes. We will recommend a hot water tank sanitation and flush.
If the smell is strong when the water in both the hot and cold faucets is first turned on, and it diminishes or goes away after the water has run, the problem could be with the faucet or faucet screen. If the smell varies through time, the problem is likely to be sulfur bacteria in the well or distribution system, and/or your pipes need cleaning.
If the smell is strong when the water in both the hot and cold faucets is first turned on and is more or less constant and persists with use, the problem is likely to be Hydrogen Sulfide (Sulfur).
The most common cause of smelly water is anaerobic bacteria that exist in some water and react with sulfur, and the magnesium and aluminum sacrificial anodes that come with most water heaters to produce hydrogen sulfide gas, making the classic rotten egg odor. The problem is most common in well systems, either private or municipal.
Softening can make smelly water much worse. By the way, don’t blame the water heater manufacturers. It’s not their fault and it’s not their responsibility. It’s just a condition that exists in some parts of the country and each person has to deal with it.
We’ve heard of plumbers or handymen advising people to remove the sacrificial anodes from their water heaters as a solution to smelly water. It’s a solution all right, but one that will ensure your water heater rusts out in record time. There is a reason why removing an anode voids all the manufacturers’ warranties.
Additionally, people have been told to replace a magnesium anode with an aluminum one. Don’t. Aluminum causes just as many rotten eggs as magnesium.
The problem may only be eliminated by drilling a well into a different formation capable of producing water that is free of Hydrogen Sulfide (Sulfur) gas or connecting to an alternate water source. However, there are several options available for treatment of water with Hydrogen Sulfide (Sulfur) gas.
Install a Gen 5 Sulfur Eliminator. This is the only option for effectively removing Hydrogen Sulfide (Sulfur) levels greater than 3 ppm. The gas is trapped by the carbon and air chamber until the filter is saturated. It then backwashes and turns the sulfur gas into a solid and does this daily. Since the Sulfur filter can remove substances in addition to Hydrogen Sulfide (Sulfur) gas, it is difficult to predict its service life. Some large carbon filters have been known to last for years, while some small filters may last for only weeks or even days.