Finishing up the morning brushing of your pearly white teeth, you pour some water into a cup to give your mouth a rinse and, Wheew, what’s that smell? You think twice about rinsing your mouth out because the water you just poured stinks of rotten eggs. Why?
Why Does My Water Smell Like Eggs? An egg smell in water is most commonly due to the presence of Hydrogen Sulfide gas. This gas is produced as a bi-product when sulfates in the water are broken down by Sulfite-reducing bacteria. An egg smell from the hot water only is often due to a reaction with the anode rod in your hot water heater tank.
Determining the source of your rotten egg smell and what to do about it will require a bit of investigating. Let’s go over a few symptoms and situations involving rotten egg smell in water and help you solve your egg odor problem.
What Is The Cause of the Rotten Egg Smell?
Since the Hydrogen Sulfide gas that is the source of the egg smell comes from bacteria breaking down sulfates in the water, any water that contains bacteria may potentially have a rotten egg odor.
Bacterias are very common in water supplies, and for the most part, they are not harmful to humans and cause no problems other than an unpleasant odor when they breakdown sulfates.
Bacteria flourishes in warm damp surroundings which would include the inside of the plumbing of a home. It will cling to the inside of the pipes and nestle in seams where plumbing fittings are used.
Once the bacteria finds a new home, it will reproduce and create a colony which will in time produce enough Hydrogen Sulfide gas to where your water will begin to have a rotten egg odor.
As the population of the bacteria increases, the strength of the odor that is produced will increase.
Is Hydrogen Sulfide gas a problem?
Average household water containing Hydrogen Sulfide gas is not considered to be unsafe to drink or cook with, and the bacteria that are the cause of the rotten egg odor, generally have no ill effects to humans or our pets.
Only at a high level does Hydrogen Sulfide gas become more than just an unpleasant smell, but the odor will usually become unbearable before there are any ill effects from the gas itself.
Hydrogen Sulfide gas is toxic, flammable at high levels and can cause irritation to the eyes and throat if inhaled.
At levels as little as 20 ppm (parts per million) symptoms of fatigue, loss of appetite, headache, irritability, poor memory, dizziness are possible. Source
Hydrogen Sulfide is a corrosive substance that will damage metals and leave unsightly black stains on metal surfaces such as sinks, silverware and cooking pots.
Finding levels of Hydrogen Sulfide gas that cause any physical damage is quite rare, for the most part, the level is very low and causes little more than an undesirable odor.
Why does only my hot water smell like rotten eggs?
This problem is much more common than you may think! If you have a hot water storage tank, there is a self-sacrificing rod inside of it called an anode rod. These rods are usually made of Aluminum, Magnesium or Zinc.
Magnesium anode rods are very common and work very well where water hardness is low and when water is free of sulfur bacteria. But they do have a tendency to react with some water and create Hydrogen Sulfide gas which gives the water a rotten egg smell.
If you are only experiencing a rotten egg smell from your hot water heater tank, changing the anode rod to an Aluminum, Zinc, Aluminum/Zinc, or Titanium anode rod will often fix the problem.
I prefer using a Titanium anode rod as it tends to be less likely to produce a sulfur smell.
Why does my water smell like rotten eggs only from some locations?
This situation will need a bit of investigating. First, we will need to find out some more details about exactly where the smell is coming from and the possible causes. Then we will go into how to remedy each of the different situations.
Is it the same smell in all of the affected locations?
In other words, does one sink smell like rotten eggs, but another smells like old garbage, and yet another has no odor at all.
To determine the situation for each location where you have the odors, follow the following steps.
1: Before running any water and when no water has been used for several hours, smell inside of the sink or shower where the smell has occurred. If you smell an odor, it may be coming from the drain or other area and not be your water at all.
You can pour 1/4 cup of regular household bleach down the drain and let it sit for about 3 hours and that may eliminate any odors coming from it.
2: Turn on the cold water only. Do you smell the same odor that you smelled before? If so, there may be sulfur in your cold water pipes leading to that location. If you do not smell any or at least very little odor, shut the cold water off and continue to the next step.
If you find that you are only getting the odor from certain sinks in the house, but not from all of them, the flexible feed lines directly underneath the sink may be the culprit.
You can easily shut off the water going to the sink and replace these lines with just a pair of pliers. You can find the correct replacement feeder lines right here.
3: Turn on the hot water only. If the water has an odor from the hot water only, you very likely have the odor originating from your hot water system. A likely cause is the anode rod in your hot water heater tank reacting with the characteristics of your water.
But if you are not experiencing sulfur odor in your hot water in all hot water locations, you may have Sulfite-reducing bacteria in the hot water pipes going to certain locations only.
If this is the case, chlorinating the hot water pipes would be your best solution.
This can be done by introducing chlorine to your well and then running it into the plumbing of your home.
This can be done using up to 2 gallons of ordinary unscented household bleach, and simply pouring them down your well, then drawing water from the well into the hot water plumbing throughout your home.
Run the hot water until you smell the bleach coming from the taps affected. Then let it sit in the plumbing for about three hours and then run the water until all of the bleach is gone.
My water smells like rotten eggs everywhere!
Rotten egg smell from all of your water outlets on both hot and cold usually means that you have a sulfur issue in the water that is entering your home. Shocking your well with chlorine to eliminate any bacteria that may be causing the odor is often a temporary fix.
The groundwater that supplies your home is likely carrying Sulfite-reducing bacteria which creates Hydrogen Sulfide gas which is the gas that produces the rotten egg smell.
If this is the case, there are ways to treat this problem.
Chlorinating the water using a chlorine injection system:
By injecting chlorine into the water, the chlorine causes a reaction with the Hydrogen Sulfide which eliminates the odor but creates a bright yellow particle that is odorless and tasteless.
Although this takes care of the rotten egg smell, there is now chlorine in the water and small particles of sulfur which have to be removed or they will yellow clothing and the chlorine may bleach clothing.
Fortunately, activated carbon works very well at accomplishing this task. After the water has been treated with the chlorine, the water will go through a tank containing activated carbon which will capture the sulfur particles and chlorine in the pores of the carbon.
This tank is automatically back-washed regularly to keep the carbon fresh so it can be used again and again.
Eventually, the activated carbon breaks down and needs to be replaced, but it will often last for several years before this is needed, and the expense of having this done, or doing it yourself is often very reasonable.
Aeration of the water:
The process of aerating the water for sulfur removal involves the introduction of additional Oxygen to water which will react with the Hydrogen Sulfide gas in the water that causes a rotten egg smell, turning it into an odorless form referred to as sulfate.
This aeration process works well for many situations, but can sometimes leave tiny air bubbles in the water that will appear when the water is depressurized after coming out of a faucet or shower.
These air bubbles are considered to be more of an inconvenience than a problem as there are no harmful effects when this happens.
Activated Carbon filtration:
The use of Activated Carbon for Hydrogen Sulfide removal from water is by far my favorite method to solve rotten egg odor. It is a very effective and clean method that requires no maintenance by the homeowner and is also chemical-free.
Hydrogen Sulfide is absorbed into the pores of the activated carbon media and then the carbon is cleaned by backwashing with ordinary water.
In most cases, the activated carbon will work well for many years and with minimal servicing.
