Water Heater Smells Like Gas But No Leak: We Find Out Why

You might be wondering why there’s a rotten egg smell in your home, but you can’t find any gas leaks. There are a few possible reasons for this smell, and we’re going to outline them in this article.

One reason for a gas-type smell yet no gas leak might be that you have a sewer leak. Sewer leaks can cause a sulfur smell, and they can also be dangerous, so it’s important to address the issue as soon as possible.

If you think you might have a sewer leak, call a professional to come and take a look.

Water heater smells but no leak

Another possibility is that you have a plumbing issue. A plumbing leak can also cause a sulfur smell, and it’s important to address this issue as soon as possible.

If you think you might have a plumbing leak, call a professional to come and take a look.

Something else to consider is that perhaps there’s something wrong with your air conditioning unit. A malfunctioning air conditioning unit can release sulfur dioxide, which will cause an unpleasant smell.

If you think there might be something wrong with your air conditioning unit, call a professional to take a look at it.

What Causes a Gas Smell When There Is No Gas Leak?

When there is no leak, sulfur or hydrogen sulfide is typically to blame for odors of natural gas in a house. In drains and sewers, microorganisms produce hydrogen sulfide. A similar odor can come from hot water heaters if they are not used and drained frequently.

Although not dangerous, these sulfur odors should not be disregarded.

Does Your Water Heater Need to be Drained?

Have you ever gone to check on your water heater and been met with the smell of gas? While it may be alarming at first, there’s usually no need to panic. In most cases, the odor is caused by a build-up of dirt and sediment in the heater.

When water is heated, it naturally starts to break down into its component parts. This process is accelerated by the presence of minerals in the water, which can leave behind a deposit of sediment.

Over time, this sediment can build up and start to cause problems. One symptom is an unpleasant smell as the sediment starts to decompose.

A water heater’s heating elements can become coated, which reduces their efficiency and could eventually cause them to fail.

The good news is that this problem can be easily fixed by draining the water heater and flushing out the sediment.

By taking this simple preventative measure, you can keep your water heater running smoothly for years to come.

There are also other reasons a water heater may need to be drained.

No one likes a cold shower, but if your water heater isn’t functioning properly, that’s exactly what you’ll be faced with. If you notice any of the following signs, it’s time to drain your water heater:

  • The water takes longer than usual to heat up
  • There is rust in the water
  • The water heater makes strange noises
  • The water temperature is inconsistently hot.

So whether you need to drain your water heater due to a buildup of bacteria or any other reason, draining a water heater can solve many problems.

Sewer Problem

Gas-like smells could actually be a sewer problem. If the gas is coming from your drains, you may have a clog in your sewer line. The gas could also be coming from your toilet. If you have a leak in your toilet, the gas could escape and cause an odor.

If you think you have a sewer problem, you should contact a plumber to have it repaired. Sewer problems can be serious and should be fixed as soon as possible.

Plumbing Problem

One common cause of bad smells from plumbing is a clog in the drain. When water can’t flow freely through the drain, it can cause an ominous gurgling sound and an unpleasant smell. Another potential cause of bad smells is sewer gas leaks.

Sewer gas is composed of methane and other gases that are released when waste breaks down in the sewer system.

If these gases escape from the sewer and into your home, they can cause a nauseating smell. In addition, sewage leaks or overflows can also lead to bad smells in your home.

If you suspect you have a plumbing problem that is causing bad smells, it’s important to call a professional plumber right away to diagnose and fix the problem.

Otherwise, you may be stuck with the stink for days or even weeks to come.

AC Unit May Need Attention

There are a few different reasons why your AC might start to smell bad. One possibility is that the filter is dirty and needs to be replaced. Another possibility is that there is mold or mildew growing somewhere in the unit.

If you suspect that this might be the case, you should contact a professional to have them take a look.

In some cases, the bad smell might just be coming from something that was left in the AC unit, such as an old piece of food.

And sadly, rodents have been known to crawl inside an AC unit, getting trapped and not being able to find their way out. They eventually die, decay, and the odor begins to permeate.

If this is the case, simply removing the item or rodent should take care of the problem.

No matter what the cause of the bad smell is, it’s always best to have it checked out by a professional to make sure everything is okay with your AC.

Am I Smelling Natural Gas?

When a natural gas leak occurs, you may smell a rotten egg odor coming from gas appliances in your home. This is because natural gas is odorless, so an additive called mercaptan is added to it to give it a sulfur-like smell.

If you smell mercaptan, it’s important to leave the house immediately and call your utility company.

Do not turn any lights on or off, unplug any appliances, or use your phone near the area of the leak.

Once you’re safely away from the house, call emergency services and explain that there may be a natural gas leak.

A fire department dispatcher will then notify the local utility company so that they can send someone out to check for leaks and make repairs.

What Causes the Smell of Sewer Gas in a House?

The most common cause of sewer gas smell in your home is a dried-out P-trap. Every drain in your home has a U-shaped curve or trap, that’s filled with water. This water forms a barrier that stops sewer gas from entering your home through the drain.

If the water evaporates for any reason, the sewer gas is no longer trapped and will escape into your home through the open drain.

Another common cause of sewer gas smell is a cracked or broken vent pipe. Vent pipes allow air to enter the DWV system so that water can flow freely down the drains.

If there’s a crack or break in the vent pipe, sewer gas will escape and enter your home.

Additional causes of sewer gas smells include gaps around plumbing fixtures and improperly installed or sealed toilet wax rings.

Is Sewer Gas Dangerous?

Sewer gas is a mix of different gases that are produced by decomposing sewage. These gases can include methane, carbon dioxide, hydrogen sulfide, and ammonia. While most of these gases are not dangerous in small amounts, hydrogen sulfide is potentially toxic and can cause headaches, dizziness, and nausea.

Sewer gas can also be explosive if it builds up in a confined space.

For these reasons, it’s important to make sure that your home’s sewer system is properly ventilated to prevent sewer gas from entering the home.

If you do smell sewer gas, open some windows and call a plumber to have your sewer system checked for leaks.

Water Heater Smells Like Gas

Do you have a water heater that smells like gas? If so, then you’re not alone. This is a common problem, and it’s usually caused by a build-up of sediment in the bottom of the tank. When this happens, it can cause a reaction with the metals in the tank, which releases hydrogen sulfide gas.

This gas is highly flammable, so it’s important to take steps to clean out your water heater as soon as possible.

The good news is that this is a relatively easy process. Start by draining the tank completely. This will get rid of most of the sediment.

Flush the tank with a hose to remove any remaining sediment, then fill the tank with fresh water and add a commercial cleaner designed specifically for hot water heaters.

Run the burner for an hour or so to circulate the cleaner throughout the system.

After that, your water heater should be good as new – and most importantly, it won’t smell like gas anymore!

Is My Water OK If My Water Heater Smells?

Have you ever stopped to wonder what that rotten egg smell could be coming from your water heater? If your water heater smells, it could be due to a build-up of bacteria in the tank. Although this bacteria is not harmful to humans, it can cause a rotten egg smell that can be quite unpleasant.

The good news is that there are some easy ways to get rid of these bacteria and improve the quality of your water. First, you can install a water filter on your cold water supply line.

This will help to remove bacteria before it has a chance to enter your water heater. You can also flush your water heater on a regular basis to remove any build-up of sediment and bacteria.

Finally, you can add an eighth of a cup of bleach to your water heater once a month to kill any existing bacteria.

By taking these simple steps, you can keep your water tasting fresh and free of unpleasant odors.

Test Your Well Water if It Smells Like Sewer

If your well water smells like sewage, it’s important to take action right away. While it’s possible that the odor is coming from something as innocuous as a nearby septic tank, it could also be a sign of serious contamination.

If you’re not sure where the smell is coming from, the first step is to contact your local health department.

They will be able to test your water to determine if there are any harmful bacteria present. In the meantime, it’s important to avoid using the water for drinking, cooking, or bathing.

If you have a private well, you should also have it checked periodically for bacteria and other contaminants.

By taking these simple steps, you can help keep your family safe from harm.

Your Septic System May Not Be Working

No one likes a bad smell in their home. Whether it’s a musty basement or a stinky garbage can, odors are always unwelcome guests. However, when the source of the smell is your septic system, it’s time to take action.

A septic system that is working properly shouldn’t produce any bad smells. If you start to notice an odor, it could be a sign that your septic system is not working correctly.

There are a few possible reasons for this. First, the vent pipe could be blocked, preventing the septic tank from venting properly.

Another possibility is that the drain field is saturated, causing wastewater to back up into the house. Whatever the cause, it’s important to have the problem diagnosed and fixed as soon as possible.

A malfunctioning septic system can cause serious health problems, so don’t wait to call a professional if you think there’s a problem.

Natural Gas Could Be Entering the Home from Outside

Everyone knows the distinct smell of a gas leak. It’s sharp, and it can be pretty overwhelming. But what if that smell wasn’t coming from inside the home? Believe it or not, a gas leak smell could be entering the home from outside.

Here’s how: if there’s a gas leak somewhere in the neighborhood, the wind could be blowing the gas toward your house.

And if there’s a crack or hole in your foundation, the gas could be seeping into your home from below.

So, if you ever notice a gas leak smell, don’t assume it’s coming from your stove or your furnace. It could be coming from outside.

Be sure to open some windows and call the gas company just to be safe.

Natural Gas Companies May Be Releasing Gas Into the Air

In some cases, gas companies may release gas into the air during regular maintenance and repairs. This is usually done in areas where there is little wind to disperse the gas. However, some people may still be able to smell the gas if it’s being released in large quantities.

If you’ve ever smelled gas while walking down the street, there’s a chance it could be coming from a gas leak at a nearby home or business. So if you notice a faint smell of gas, don’t ignore it!

Call your local utility company and ask them to check for any potential leaks in the area. Never assume there must be repair work or maintenance being done in the area. Reporting a suspected gas leak could save lives.

Gas leaks can happen when pipes are damaged or when fittings become loose. While most gas leaks are small and pose no threat, they can still be dangerous if left unchecked.

If you suspect a gas leak, it’s important to call your local utility company immediately.

How to Know if There Is a Gas Leak Outside?

There are a few warning signs that can indicate if there is a gas leak outside. Do you notice any of the following?

  • Dead grass or plants could be a sign that there is a gas leak.
  • Bubbles in puddles of water – those could be caused by gas escaping from underground gas lines.
  • A hissing noise, that’s another potential sign of a gas leak.

If you suspect there might be a gas leak, it’s important to leave the area immediately and call your gas company.

Don’t try to fix the problem yourself – let the professionals handle it.

Gas Smells Coming from Neighboring Apartment

If you smell gas coming from a neighboring apartment, it’s important to take action immediately. Gas leaks can be dangerous, and even a small leak can quickly lead to an explosion. The first thing you should do is open all the windows in your apartment to ventilate the area.

Then, call the gas company and explain the situation. They will send someone out to check for leaks and make sure everything is safe.

In the meantime, try to avoid using any electrical appliances or devices that could create a spark, as this could potentially ignite the gas.

If you follow these steps, you can help prevent a gas leak from turning into a disaster.

Apartment Buildings Have Other Reasons to Smell

If you’ve ever lived in an apartment building, chances are you’re familiar with the occasional gas leak. While these leaks are certainly one reason why your building may smell, they’re certainly not the only reason.

Here are a few other potential sources of undesirable odors in apartment buildings:

Wet Clothes Left in the Laundry Room

If you’ve ever forgotten to bring your wet clothes up from the laundry room, you know that they can start to stink pretty quickly.

Not only is it important to take your clothes out of the washer in a timely manner, but it’s also important to hang them up or put them in the dryer as soon as possible.

Otherwise, you may end up with smelly clothes – and a smelly apartment.


While we love our fur babies, they can sometimes be the source of undesirable odors.

From pet food to litter boxes to accidents on the carpet, there are many ways that our furry friends can make our apartments smell less than fresh.

If you have a pet, be sure to take good care of them and keep their areas clean to help minimize odor problems.


Whether it’s old food in the fridge or garbage that hasn’t been taken out, trash is one of the most common sources of bad smells in apartments.

Be sure to throw out any old food and take your garbage out on a regular basis to help keep your apartment smelling fresh.

While gas leaks are certainly one reason why your building may smell, they’re certainly not the only reason.

These are just a few of the potential sources of bad odors in apartment buildings.

By being aware of these potential problems, you can help keep your apartment smelling fresh and clean.

Final Thoughts

The smell of what we think is a gas leak can be very alarming, to say the least. Your first step should always be to first treat a sulfur smell as if it is indeed a gas leak, as gas leaks are often associated with dangerous situations, and rightfully so.

A water heater that smells like gas but has no gas leak is likely caused by another reason such as the water heater simply needing to be drained.

Ruling out a gas leak first will help prevent a potential water heater explosion from a true water heater gas leak.

Once a gas leak has been ruled out, we can then play the process of elimination with the other options for what may be causing the gas-like smell.


Trina Greenfield, Author
SmackDown Media LLC

About the Author:
Trina Greenfield, the owner of SmackDown Media LLC, is passionate about providing information to those interested in the air quality in and around their homes. Trina writes content about things she’s passionate about, such as safe, in-home air, educational platforms for children and adults, as well as all things family-related.