Why Does My Well Water Smell Like Rotten Eggs and Sulfur? (2024)

Reviewed by: James Layton
Updated on:
February 27, 2024

Water with an unpleasant odor or taste resembling sulfur or rotten eggs indicates the presence of hydrogen sulfide gas (H2S).

Key Takeaways

  • Before you can fix it using one of the solutions I list below, you first need to identify the source.

Luckily, rotten egg smell in well water is a common phenomenon in privately owned well water systems and doesn’t always require a professional plumber to solve.

That said, keep reading because the exact solution depends on a few factors.

Identifying the Source of Well Water Rotten Eggs Smell

Don’t jump to conclusions and immediately blame your well. Check to see if the problem lies elsewhere. Investigate these possible sources first:

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

Determining whether the smelly sulfur water is coming from a hot or cold faucet will lead you to the answer.

  • If 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 to jump to the solution.

  • Supposing the sulfur smell is present in cold water, your problem may be with the water softener.

    If so, click here to jump to 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 to jump to the solution.

  • Should the rotten egg smell persist after running the tap for a few minutes, the problem lies in the groundwater.

    Click here to jump to the solution. 

How to Fix the Rotten Egg Odor in Well Water

The solution to your rotten egg odor depends on the source of the problem. Below are likely sources and the steps to solving your problem.

Source 1: Water heaters

There are two possible reasons 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. In no time, all the bacteria will be gone, and your water system will smell fresh. 

You can find instructions online for how to do this, but it may be best to hire a professional.

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 best way to solve a hydrogen sulfide problem. It’s a last-ditch effort.

If the problem is within your pipes, chlorination is the best solution.

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. Choose from our curated list of the best water softener cleaners.

If the problem persists, contact the water softener contractor, and always remember that maintaining your water softener properly is essential to its continued function.

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. This process is called “shock chlorination.”

Shock chlorination will kill the sulfur and iron bacteria in the pipes and at the source, resulting in fresher 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.

In the meantime, you may want to install a filter. We reviewed the best filters designed to remove sulfur from well water.

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 whole-house water treatment systems.

Such systems can treat sulfur water, but be sure to test your water for other contaminants before investing.

A home water treatment system can cost thousands of dollars depending on its capacity and treatment capabilities, and you want one that will address the specific issues your home faces.

Again, here’s our list of the seven best whole-house filters for removing sulfur from well water. Take a look and find one that suits your home and family best.

Install point-of-use water filters.

Point-of-use water filters are easy to install and much cheaper than treatment plants, but they are not as effective, simply because they treat water at a single point of use, usually under the kitchen sink, rather than all the water entering the home.

You can try reverse osmosis (RO) filters, oxidizing filters, mechanical filters, ozonation filters, and activated carbon filters in your house. All are popular, effective methods for treating a variety of contaminants, including sulfur.

Drill a new well.

Drilling a new well in a different position may sometimes be the only viable and economical solution. The cost of drilling a well will depend on a variety of factors specific to your property.

Instead of spending money on treatment plants that may only be a Band-Aid for an ongoing problem, consult a 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 cause 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. 

The easiest solution is usually a water treatment system.

No matter what the problem, you can easily identify the source and possible solutions to the problem by going through the above guide. It’s safe to use the water until the problem is sorted.

For more information about well water in general, check out the following guides and reviews:

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