Causes of sulfur smell

Causes of Sulfur Smell


Clean drinking water. It’s something most of us take for granted. There is nothing better after a long bicycle ride. You are drenched with sweat. You go to your kitchen, turn on your faucet and pour yourself a tall glass of water. Nothing quenches your thirst like good, clean water. But what if you're water smells of rotten eggs, permeates your nostrils, and you have to resort to bottled water? Consider yourself lucky if you haven’t had to experience this. If your water smells like rotten eggs, you most likely have hydrogen sulfide gas in your water supply. Hydrogen sulfide gas occurs naturally in some water as a result of chemical reactions with rocks and soil. It can also be produced by sulfur reducing bacteria breaking down organic matter in groundwater, or a chemical reaction inside water heaters.

Is water that smells like sulfur harmful?

Sulfur bacteria are not harmful, but can help other bacteria grow, such as iron bacteria, which are also not harmful. Hydrogen sulfide gas in the water doesn’t necessarily pose an immediate threat to your health. It's not usually a health risk at the levels normally found in household water. Although, if there are high amounts of sulfur in your water supply, you may be at risk of diarrhea which can lead to dehydration. Large amounts of sulfur can lead to stained sinks, appliances and clothing. If left untreated for a long period of time, sulfur can cause corrosion in your water pipes and yellow or black stains on your plumbing fixtures. Even though having sulfur in your plumbing system might not be harmful to you and your loved ones, the mere presence of it is an indicator of pollution or chemicals that could be damaging to the health of you and your family.

How to test for sulfur in domestic water

The very first step of removing sulfur from your water supply is to locate the source of the smell. This is usually below ground in your well. If you have a well that’s drilled into acidic bedrock like sandstone or shale, or is in close proximity to a coal mine or oil field, then the presence of sulfur is much more likely than normal.

Another possible source of the smell could be your water heater. The magnesium anode rod in your water heater is meant to prevent corrosion but it can chemically react with sulfate reducing bacteria, present in many water systems, to produce hydrogen sulfide. If you only notice the sulfur smell when your hot water is running out of your faucet, it is a good sign that the magnesium rod in your water heater needs to be replaced. If you are going to replace the anode rod, you should use an aluminum, zinc, tin, anode rod. This combination anode rod will not only help protect your water heater without using magnesium, but has the added benefit of zinc. Zinc is a natural anti-fungal mineral that can help deter the growth of iron bacteria which can also cause a rotten egg smell.

If your hot and cold water smells and tastes like rotten eggs, you should have your water tested. You can purchase a water test kit and do the test yourself. There are many available options ranging in price depending on how extensive you want your test to be. Test kits will usually include instructions and questions to answer that help gauge what is wrong with your water. It is very important to fill out the questionnaire as it will help determine the cause and presence of pesky bacteria. If you don't wish to tackle testing your water on your own then you should have your water tested for hydrogen sulfide by a professional. A state certified laboratory will be able to determine the exact cause of the odor, and reveal any other contaminants in your water. A test like this will also show you how much of each contaminant is in your water so you can take the proper steps to completely correct any water quality issues.

How to treat sulfur contaminated water

How you treat sulfur contaminated water depends on the level of hydrogen sulfide or sulfates in your water. There are a few treatment options. The most common method is to install a whole-house treatment system. An aeration system is often used if hydrogen sulfide concentrations are lower than 2 ppm. Hydrogen sulfide can be removed by injecting air into the water, allowing the hydrogen sulfide gas to escape. However, granular activated carbon filter may need to be used after the aeration system to remove any remaining solids that form from the aeration process. This type of system can be advantageous because no chemicals are added to the water, and can also help in reducing some levels of iron and manganese. There are some disadvantages if your water has a high pH or during periods of high water use which can cause aeration to be less effective.

Iron removal filters using manganese greensand can remove up to 10 ppm of hydrogen sulfide in addition to removing iron and manganese. The manganese greensand chemically reacts and oxidizes the hydrogen sulfide transforming it into a solid form which can then be removed by a filter.

Chemical oxidation, using chlorine bleach or hydrogen peroxide, is another method of removing the sulfur. Chlorination systems use either a liquid chemical feed or a dry pellet dispenser to add chlorine either into your water system after the pressure tank or directly into the well. The chlorine bleach reacts and oxidizes the hydrogen sulfide reducing it to a solid (sulfur) which can then removed with a sediment filter. Hydrogen peroxide can also be used to oxidize hydrogen sulfide with the use of a a liquid chemical feed pump providing the same results as the chlorine.

Choose wisely

Before choosing a system, consider not only the best treatment method for your situation but also the initial cost and operating costs that will be needed to treat your water. Hidden costs can add up, like replacement filters, electricity usage, chemicals, maintenance supplies and some systems will require extra water for back washing. Some of these systems may seem expensive, but may be your best option if you want to get rid of the rotten egg smelling, bad tasting water.

There is another option but it's even more costly. A new water source may be needed, but drilling a new well in a new location will not be cheap. You should only consider doing this in extreme situations where other methods don’t work for you. If the amount of hydrogen sulfide is minuscule, you can try boiling the water you use for cooking and drinking. Once the water has been boiled and cooled, it should be safe to consume and the smell should also be gone.

Final thoughts

The presence of sulfur in your water can be very irritating. Although it doesn’t usually pose serious health risks, it can stain your plumbing fixtures, cookware and clothing. If the smell is very strong, it can permeate your entire home. The great news is that it can be very easy and inexpensive to test for sulfur. In many cases switching out the magnesium rod in your water heater is all it takes to fix the problem. If the system options listed are too costly, you can always drink bottled water.

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