My Well Water Smells Like Rotten Eggs! How Can I Fix It?

By: Jake Gallagher | August 23, 2023

Do you smell something fishy in your well water? Maybe a rotten egg odor? If so, don’t fret. Well water smells for many reasons—the most common being the presence of sulfur bacteria.

With just a little look-see, you can easily identify the root cause of sulfur in your well. I’ll walk you through the steps and explain the solutions to get rid of the odor quickly.

Now, let’s take care of that sulfur smell.

Key Takeaway

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Why Does Your Well Water Smell Like Rotten Eggs? 

You must be wondering what causes this nasty rotten egg odor in the first place. Water with an unpleasant odor or taste resembling “rotten eggs” may be an indication of the presence of hydrogen sulfide gas (H2S), which can be found in wells across various locations. This gas can:

  • Naturally due to the decay process and chemical reactions involving soil and rocks.
  • Water softener
  • It can also be the result of water coming from plumbing systems or pipes contaminated with sulfur bacteria.
  • Or due to a simple chemical reaction in your water heater.
  • Sometimes, local runoff can also pollute your well. This only happens if your wellhead is not properly sealed. Underground sewage pollution is also possible.

But don’t worry, sulfur-causing bacteria is not harmful, or in biological terms, “coliform.” However, the stink itself can create an unappealing taste in your drinking water and even make you nauseous.

It’s a highly common experience in privately owned well water systems and doesn’t always require a professional plumber to solve, unless you’re afraid of wells and pipes.

How to Identify the Source of Well Water Rotten Eggs Smell

Before jumping to conclusions and blaming the water well, check to see if the problem lies elsewhere. Ruling out minor issues first will save you valuable time and money. So, here are the possible sources of a well water rotten eggs smell:

  • Hot water heater
  • Water softener
  • Well water and plumbing system
  • Groundwater

Start by checking whether the smelly sulfur water is coming from a hot or cold faucet.

  • Check the hot and cold water. If the hot water gives off a rotten egg smell and cold water is okay, then the water heater and the connected plumbing system are the probable causes. Click here for the solution.
  • Supposing the sulfur smell is present in cold water, check whether the faucet is connected to the water softener. You should investigate multiple taps around the house to see if only the water treated by the water softener has the smell. If so, click here for the solution.
  • Once you rule out the above possibilities, proceed further with the tests. If the smell diminishes by running the tap water for a few minutes, the problem is in the well and plumbing system. Click here for the solution.
  • Should the rotten egg smell persist after running the tap for a few minutes, you’re out of luck. The problem is serious and lies in the groundwater. Click here for the solution. 

How to Fix the Rotten Egg Odor in Well Water

Source 1: Water heaters

There are two possible reasons why your water heater may be the culprit of that eggy sulfur odor:

The magnesium anode in your water heater needs replacing

Ready for some science? 

A magnesium anode (also known as a magnesium rod or sacrificial anode) in the water heater sacrifices itself with time and prevents the storage tank from corrosion. Corrosion attacks the magnesium anode rod first because it’s a weaker metal than the steel from which the tank is made.

Unfortunately, these anodes have an expiration date and stop working when they’re 50% corroded. The corrosion layers formed on the anode produce hydrogen sulfide gas and are directly responsible for the stinky stench in the water. Hydrogen sulfide gas is usually present when the water heaters are a couple of years old.

Replace the magnesium rod with a newer one. It’s an easy process if you’re handy with tools. There are alternative anodes available that work better and last longer. 

Consider an aluminum rod anode that works on the same principle but is more durable. Another option is a powered anode with a titanium rod and circuitry that introduces a small charge in the water that keeps corrosion at bay.

If it’s a little too difficult for you to understand, contact the heater manufacturer and let the experts handle the rest.

Your water pipes are contaminated

Once you’re sure that the household water heater is well maintained, you can proceed to checking the next possible source of the problem. Sometimes sulfur, iron, and coliform bacteria pollute the supply line and pass on an unpleasant rotten egg smell to the water that runs through it. 

Flush the water pipes with chlorine bleach or other disinfectants, such as hydrogen peroxide. Here’s a guide to cleaning your well water pipes with hydrogen peroxide. Within no time, all the bacteria will be wiped off, and your water system will smell fresh. 

There is another way to kill these sulfur-reducing bacteria (they’re called that because they live off sulfur energy) if you don’t have chlorine bleach disinfectants available. Raise the water heater temperature to 160°F (70°C) and let it stay that way for several hours. This kills the bacteria, and the sulfur smell diminishes. Let the hot water tap run for a few minutes afterward to remove dead bacteria. However, this is not the recommended way. Be sure to consult the water heater manufacturer before going down this road.

Source 2: Water softener

Most houses in the US have ion exchange water softeners. There could be a sulfur buildup in it that’s causing the infamous rotten egg smell.

First, try replacing the salt and cleaning the ionic resin in the water softener. Most modern softeners can automatically run this cleaning cycle, so you just have to press the right button on the unit. Consult the technical guide that comes with the machine.

Second, flush the plumbing system with disinfectants to remove any sulfur bacteria in the pipes and the machine. You can use any high-quality store-bought disinfectant for this. If the problem persists, contact the water softener contractor.

Source 3: Well water and plumbing system

Problems in well water and plumbing systems can be resolved by disinfecting them with a chlorine bleach solution. Shock chlorination will kill the sulfur and iron bacteria in the pipes and the source, resulting in fresh drinking water and less odor.

You can hire a licensed well contractor for the disinfection. If you plan to do it yourself, consult this well-disinfection official guide for instructions.

Source 4: Groundwater 

Groundwater refers to the underground water reservoir that is the source of your private well. Unfortunately, there isn’t a quick fix to this problem, but still, there are ways you can clear the groundwater and remove the smell. 

Install water treatment plants

Such plants can treat sulfur water in homes, but installing these might cost you a lot. A home water treatment plant can cost thousands of dollars depending on its capacity and treatment capabilities.

Install water filters

Water filters are easy to install and much cheaper than treatment plants, but they are not as effective. You can try reverse osmosis (RO) filters, oxidizing filters, mechanical filters, ozonation filters, and activated carbon filters in your house.

Drill a new well

Drilling a new well in a different position may sometimes be the only viable and economical solution. So, instead of wasting money on treatment plants, consult the licensed well contractor for an expert opinion.

Is Smelly Water Okay to Drink?

Although the rotten egg smell is off-putting, the sulfur water itself is not harmful to drinking water. The sulfur bacteria that causes this smell isn’t toxic to humans. So feel free to use the water until the problem is taken care of.

However, be aware of hydrogen sulfide concentrations that are produced by the sulfur bacteria in water reservoirs. Harmful concentrations of hydrogen sulfide in water are highly toxic and can harm the nervous system. You should consider hiring someone for hydrogen sulfide testing. Only professionals should enter confined places suspected of containing hydrogen sulfide gas.

Final Thoughts

If you smell rotten eggs in your well water, you don’t need to panic. Rotten egg smell in the water supply is a common occurrence and, in most cases, the result of contaminated plumbing systems. Having new wells drilled or having someone test for hydrogen sulfide may be inconvenient, but luckily they’re unlikely worst-case scenarios. 

No matter what the problem, you can easily identify the source and possible solutions to the problem by going through the above guide. Also, feel free to use the water if necessary, until the problem is sorted.