There are three common sulfur contamination issues: sulfur bacteria, hydrogen sulfide gas and iron bacteria. These problems can be encountered in various concentrations across the entire nation. But they tend to be found in higher concentrations in private well water sources. In smaller concentrations, they are hard to detect, but higher concentrations are accompanied by a distinctive rotten egg odor.
The conditions in underground wells are an ideal environment for sulfur contamination problems. But contamination can occur in poorly serviced water treatment and home plumbing systems too. Let’s take a look at these sulfur contamination sources in more detail:
Sulfur Bacteria
These are microorganisms that thrive in warm and low oxygen sulfur rich environments, such as water heaters, water softener systems and private wells. A water heater is the most common environment because the water is kept at a warmer temperature. Sulfur bacteria can generate hydrogen sulfide gas and it may even be the cause of the rotten egg odor in isolation. This can occur if the sulfur bacteria grows for a prolonged period with no cleaning or maintenance.
Hydrogen Sulfide Gas
This is a colorless gas, the source is typically natural, but there are uncommon manmade sources too. In nature, hydrogen sulfide gas forms when animal and plant materials decompose or if sulfur bacteria is growing in low-oxygen environments.
Some common sources of hydrogen sulfide gas include natural gas deposits, sewage treatment, food processing, natural gas plants, paper pulp operations, manure handling, stagnant water, sulfur springs, swampland, and crude petroleum.
If a private well has no proper wellhead protection organic decomposing material can enter the well. Then the bacteria can feed on the material creating a low-oxygen environment which can form hydrogen sulfide gas. If you are a private well water user and you live in close proximity to food processing plants, agricultural areas or to a petroleum storage facility, your water is more at risk. Water that contains hydrogen sulfide gas will not smell bad until it comes out of the tap. Even a low concentration of 0.1 mg/L will have a noticeable foul odor. At a concentration of 100 parts per million (ppm) can actually paralyze olfactory nerves which makes the odor imperceptible for most people.
Iron Bacteria
This is a microorganism that forms when iron or manganese mixes with oxygen in soil and/or groundwater. These are abundant minerals and iron bacteria is very common. This bacteria has a musty sulfurous odor and it’s slimy to the touch. It’s easy to identify because it has a distinctive red, brown and rusty appearance and it sticks to surfaces. It’s common to find iron and sulfur bacteria growing alongside each other and they can clog plumbing systems and private wells.
What are the Health Risks?
The health risks are relatively low and to experience any ill effects, it would be necessary to drink water with very high concentrations of sulfur bacteria, hydrogen sulfide gas or iron bacteria. But, exposure to 20 ppm or above can lead to dizziness, poor memory, fatigue and a loss of appetite. The good news is that at these levels of concentration the water would be unpalatable for drinking and cooking.
There are no serious long-term health risks, but it is possible to experience diarrhea, dehydration and stomach cramps. Some preliminary EPA and WHO studies have stated that long-term and low-level hydrogen sulfide exposure is toxic. But, at this time there is no clear understanding of the risks.
Can Sulfurous Water Damage My Home?
The short answer is yes. Although the health risks are low, there are other risks to the home that should be considered. Iron bacteria can discolor sinks and toilet bowls with reddish-brown stains that are hard to clean. The sulfur and iron bacteria can clog the pipes which may lower the water pressure. Hydrogen sulfide can tarnish silverware with black stains and corrode plumbing pipes. There may also be black and yellow stains on laundry and plumbing fixtures too. These contaminants are a common cause of damage to water heaters, water softeners and other water treatment systems. So, it’s important to schedule essential annual maintenance for water using appliances if you use private well water.
How Can I Remove Sulfur from My Water?
Removing the rotten egg odor from your drinking water may not be a health priority, but these contaminants can cause a number of other problems in your home. So, it’s a good idea to identify the source of the problem and to fix it. There are four common sulfur odor sources: the water heater, groundwater, water softener and well water/plumbing system. Let’s look at them in more detail.
1. The Water Heater
Run some hot water at the sink followed by cold water. If the hot and cold water smell like rotten eggs, then your water heater is not the cause of the problem. But, if the cold water has no discernible odor and the hot water smells bad, the water heater is the source. To fix this issue, schedule some maintenance for the water heater or consider a replacement for an older unit.
2. Groundwater
Shock chlorination is an effective short-term solution, but the problem will inevitably return later. Investing in a whole house water filtration system will provide lasting protection, but not all filters remove hydrogen sulfide. A system that can inject chlorine into the water to clean and oxidize the hydrogen sulfide and bacteria will be effective. This needs to be followed by a final granular activated carbon filter stage to remove the chlorine.
3. The Water Softener
A water softener will not remove sulfur odors from water and it may be the source of the contamination if it’s not serviced regularly. Disconnect the faucet from the water softener to see if the sulfur odor persists. If it dissipates, this means that the water softener has sulfur bacteria growing inside and it needs some professional maintenance.
4. The Well and Plumbing System
If you run the water for a few minutes and the sulfur odors fade, this may mean that some deep cleaning is required in the well. The iron and sulfur bacteria needs to be scrubbed with a chemical treatment and then disinfected with shock chlorination. The well cap needs to be in good shape with adequate ventilation to prevent a buildup of hydrogen sulfide gas.
If you have sulfur related water quality issues, contact your local water treatment specialist.