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What to Do if Your House Smells Like Gas but There’s No Leak

Gas leaks are scary situations because they can be deadly if you stay in your home. That’s why companies tend to put a chemical called mercaptan in natural gases and propane. This replaces their naturally odorless qualities with a rotten egg-like sulfur smell so that you know when they’re leaking.

But this rotten-egg smell can also come from a gas called hydrogen sulfide. This can lead to discoloration in your kitchen and bathroom and may even change the taste of food.

There are also sulfur bacteria, which produce slime and cause other bacteria to grow more. It can clog up your plumbing and irrigation systems, as well as your well, if you have one.

The gas you’re experiencing could be coming from:

  • Your water heater due to chemical reactions of the metals with the sulfates in the water.
  • Sulfur bacteria in your plumbing system, water softener, groundwater or well.
  • Chemical reactions from decaying.

Here’s how to react if your home smells like gas but you have no leak

It can be super frustrating if you’ve got a home that smells like a gas leak, and you’re not sure where it’s coming from. But there are steps that you can take to figure this out.

One of the first things to do is figure out whether the odor that you’re experiencing is coming from water or from a different source.

  • If you have no smell from cold water, the problem is likely in the water heater.
  • If you have a smell from cold water, then you want to check faucets that aren’t connected to any water softener. Do these have the same smell? If not, there may be sulfur bacteria in your softener.
  • If they do have the same smell, then let the water run for a few minutes and see if that smell gets any better. If it doesn’t, you probably have hydrogen sulfide gas in the groundwater. If it does, the issue could lie in your well or plumbing system.
  • If you think your problem is not water based, then you should check your drywall or ductwork.

That’s a lot to process. But don’t worry. We’re including more detailed information about all of these steps below to help you figure this out.

1. Look at your water heater

As we mentioned previously, the problem is likely with your water heater if you’re only getting a rotten egg smell when the hot water is on. There are a few different reasons why this could be happening.

The most common issue is sulfur bacteria in your hot water tank. These bacteria produce hydrogen sulfide gas. That gas will, ultimately, dissolve into your water and give it the smell of rotten eggs. The good news is that these bacteria aren’t dangerous to your health, even though they smell bad.

It’s also possible that a chemical reaction is taking place and causing the smell. Your water may have lots of magnesium in it, and that could be reacting against the anode rod that you have in your water tank.

Anode rods are a protective feature. Their purpose is to take in all of the corrosive minerals in the tank so that they don’t corrode the tank itself. These are made of magnesium or aluminum, usually.

To get rid of the smell, you typically want to use a chlorine bleach solution to flush and disinfect your tank. You can also increase the water temperature to 160 degrees for a few hours to kill the remaining bacteria.

If you want to avoid experiencing a similar problem in the future, it could make sense to upgrade to a zinc or aluminum-zinc alloy anode rod.

Do you use well water? If so, you may need a plumber to come over and perform a chlorination treatment to kill any bacteria from the well that may be getting into your water heater.

2. Check out your drainpipes

It’s also possible that the smell you’re getting is sewer gas, which can get into your home from an empty plumbing trap. This is common in homes that have sinks, tubs, and showers that aren’t used very often. Sewage gas contains methane, which smells like rotten eggs.

Every drain in your home connects to a sewer pipe. But plumbers install a U-shaped fixture called a “trap” to eliminate the spread of sewage gases in your home.

This part is designed to retain enough water to prevent any sewer gases from going back up through the pipes and into your home. But if you haven’t used a drain for a few weeks, there won’t be enough water in the trap, and the gas can get into your house.

The good news is that fixing this problem is a pretty straightforward endeavor. You begin by following your nose to see where the smell is strongest.

Then, once you’ve located the problem pipe, turn on the faucet for a few seconds and let the water flow down into the drain. This should fill up the trap and stop any additional sewer gases from getting into your home.

You may notice that the smell is strongest in your basement. If so, you’re going to want to take a pitcher of water and pour it down the floor drain to fix the problem.

3. Look at your plumbing system, water softener, and well

The next thing you can do is check to see if you’re having a problem with some other part of your well, plumbing system, or water softener.

For example, maybe you’ve got a broken drain pipe somewhere that’s allowing these sewage gasses to get into your home. You could have clogged drain vents or some other issue that’s causing this smell.

Let’s first consider this scenario. If you use a well to get water in your home, the problem could be coming from hydrogen sulfide gas. You can spot this by looking for black stains on silver and corrosion on pipes.

You can also test for this issue by:

  1. Not running any water in your home for 6-8 hours so that the gas builds
  2. Putting a stopper in the sink and running a few inches of cold water from the tap

If you get the smell, it’s probably hydrogen sulfide. The answer is to disinfect both the well and your plumbing with a chlorine solution. You may want to hire a professional to help you out with this.

If you believe that there are bacteria in the water softener, then you probably want to contact the manufacturer for help.

4. Inspect your drywall

The next thing that you can do is check your drywall to see if the problem could be coming from it. Chinese drywall, which was commonly used between 2003 and 2007, has high levels of sulfur, which can cause the smell that you’re experiencing.

There are a few things that you can consider to see if this might be your problem.

  • First, was your drywall installed between 2002 and 2009? If not, then this probably isn’t your issue. If yes, keep going.
  • Do you have any blackening of copper components in your home? This can be caused by hydrogen sulfide.
  • Do you notice any other evidence? For example, you might see Chinese lettering on the drywall.

If you think that this is your problem, consider calling your insurance agent. You may be able to get some help paying to fix the issue.

5. Check out your ductwork

If you smell gas, but you are sure there is no leak, it may be due to a dead animal that has become trapped in your ductwork somewhere.

If you suspect this is the case, you should start by pinpointing the specific vent where the odor is most intense. Next, you can use a screwdriver to remove the cover plate and look for the animal. If you locate it, extract it and clean the area.

What to do if you suspect a gas leak

Up until now, we’ve covered a lot of different sources of a gas smell that aren’t dangerous. But it’s also worth considering that you may be wrong and actually have a gas leak in your home.

If you smell a lingering propane scent, it’s time to take action—especially if that scent is accompanied by a hissing sound. Here’s what to do.

Don’t set off a spark

First, take care not to set off the spark. Don’t start your car, light any matches, or use any device that has a battery. As doing so could light the gas fumes and send your home up in flames.

Leave immediately

Next, get out of your house immediately. Even if the smell is very faint, it’s not something that you want to risk. Be sure to get a safe distance away from your home, not just to the backyard, to make sure your family is safe.

Don’t try to put out a gas fire

Finally, if you do end up getting a gas fire, don’t do anything to try and put it out. Your next step is to call the fire department and your gas company. Attempting to solve this issue on your own is very dangerous and potentially life-threatening.

Michael Joseph