Sewage Smell In House Comes And Goes: Troubleshooting And Solutions

Hey there, homeowners! Have you ever experienced that unpleasant sewage smell in your house that seems to appear out of nowhere and then mysteriously disappears? You’re not alone. Many homeowners face this issue, and it can be quite frustrating. In this blog post, we’ll delve into the possible reasons behind this sewage smell and provide you with practical solutions to get rid of it for good.

Importance of Addressing the Issue

sewage smell in house comes and goes

Before we dive into the details, let’s discuss why it’s essential to address this sewage smell issue promptly. Firstly, the smell itself is unpleasant and can cause discomfort, making it challenging to enjoy your home. Secondly, and more importantly, the presence of sewage smells can indicate underlying problems with your plumbing system. Ignoring the issue may lead to potential health hazards, as inhaling harmful gases and being exposed to bacteria and pathogens can pose risks to you and your family’s well-being.

Possible Reasons for Sewage Smell

Now let’s explore the possible reasons behind the intermittent sewage smell in your house. Understanding these causes will help us identify the source of the problem and take appropriate measures to eliminate the smell once and for all.

  1. Dry P-Traps
  2. Blocked Vents
  3. Sewer Line Damage
  4. Clogged or Blocked Drains
  5. Sewer Line Backups
  6. Faulty Plumbing Connections
  7. Improperly Vented Appliances
  8. Sewer Gas Leaks
  9. Dry Soil or Floor Drains

Identifying the Culprit: Explanation and Details

Dry P-Traps

One of the most common causes of intermittent sewage smells is dry P-traps. P-traps are U-shaped pipes located under sinks, showers, and other fixtures. They are designed to hold water, creating a barrier that prevents sewer gases from entering your home. When a fixture is not used regularly, the water in the P-trap can evaporate, leaving an open pathway for sewage odors to waft into your living space. To solve this issue, simply run water in unused fixtures to refill the P-traps and block the smell.

Blocked Vents or Poor Venting System

Your plumbing system features vents that allow air to flow through the pipes, maintaining proper pressure and preventing odors. However, if these vents become obstructed by debris, leaves, or even animal nests, sewer gases can build up and find their way into your house. In order to tackle this issue, it’s important to inspect and clean your vents regularly. Clear any blockages and ensure proper airflow to keep those sewage smells at bay. If you find out that smell come from exact from vents then then read this for troubleshoot: Sewage Smell Coming From Air Vents?

Sewer Line Damage

Damaged sewer lines, such as cracks, leaks, or breaks, can lead to intermittent sewage smells invading your home. The smells may come and go depending on factors like water usage or changes in external pressure. It’s crucial to address sewer line damage promptly to prevent further issues. Contact a professional plumber to inspect and repair any damage to your sewer lines, ensuring the integrity of your plumbing system.

Clogged or Blocked Drains

Another common culprit for sewage smells is clogged or blocked drains. Accumulated debris, grease, or foreign objects can obstruct the flow of wastewater, resulting in foul odors seeping back into your house. To combat this issue, you can start by using a plunger or a drain snake to clear minor blockages. For more stubborn clogs, consider using a drain cleaner or contacting a professional plumber for assistance.

Sewer Line Backups

A blocked or obstructed main sewer line can cause sewage to back up into your home, resulting in a strong and persistent sewage smell. This issue requires immediate attention as it can lead to significant damage and health hazards. If you’re experiencing sewer line backups, it’s essential to contact a professional plumber who can assess the situation and perform the necessary repairs or cleaning to restore proper flow and eliminate the smell.

Faulty Plumbing Connections

Improperly installed or damaged plumbing connections can be another reason behind those unpleasant sewage odors in your house. Leaky seals or loose fittings around pipes, toilets, or fixtures can allow sewer gases to escape into your living space. Check for any visible signs of leakage, such as water stains or dampness around connections. Tighten loose fittings or replace damaged seals to prevent further odor issues.

Improperly Vented Appliances

Appliances such as washing machines, dishwashers, or garbage disposals generate odors and gases during operation. These appliances require proper venting to release these odors outside your home. If they are not adequately vented, the sewage smells can make their way into your living space. Make sure that all your appliances are correctly vented, and if you suspect any issues, consult a professional technician to assess and rectify the ventilation system.

Sewer Gas Leaks

Sewer gas leaks within your house can occur due to damaged or deteriorated pipes, fittings, or seals. These leaks can result in intermittent sewage smells that vary in intensity depending on factors such as temperature and air pressure. Identifying and fixing these leaks is crucial for maintaining a healthy living environment. Inspect your plumbing system for any visible signs of leaks, such as water stains, mold growth, or hissing sounds. Contact a professional plumber to assess and repair the leaks to eliminate the odors completely.

Dry Soil or Floor Drains

Soil or floor drains located in basements, laundry rooms, or garages can also contribute to sewage odors if they accumulate debris or dry out. A dry drain can allow the odors to escape into your home. To tackle this issue, pour water down the drains periodically to ensure they remain filled, creating a barrier against sewage smells.

How to Get Rid of Sewer Smell in House: Step by Step

Now that we have explored the possible causes behind the sewage smell in your house, let’s discuss the step-by-step solutions to help you get rid of the odor for good:

  1. Run water in unused fixtures to refill dry P-traps and create a barrier against odors.
  2. Inspect and clean vents regularly to ensure proper airflow and prevent blockages.
  3. Contact a professional plumber to inspect and repair any damage to your sewer lines.
  4. Use a plunger or drain snake to clear minor clogs in your drains. Consider drain cleaners or professional assistance for stubborn blockages.
  5. Address main sewer line backups promptly by contacting a professional plumber for repairs or cleaning.
  6. Check and tighten any loose fittings or replace damaged seals around plumbing connections.
  7. Ensure that your appliances are properly vented to prevent odors from entering your home.
  8. Inspect your plumbing system for leaks and contact a professional plumber to repair any identified issues.
  9. Regularly pour water down soil or floor drains to maintain a water barrier against odors.

By following these steps and addressing the specific issues causing the sewage smell in your house, you can eliminate the odor and create a fresh and pleasant living environment.


Why does my house randomly smell like sewer?

There can be several reasons why your house randomly smells like sewer. It could be due to dry P-traps, blocked vents, sewer line damage, clogged or blocked drains, sewer line backups, faulty plumbing connections, improperly vented appliances, sewer gas leaks, or dry soil or floor drains. Each of these issues can allow sewer gases to enter your house, resulting in the unpleasant odor.

Does sewer smell come and go?

Yes, sewer smell can come and go. The intermittent nature of the smell can be influenced by various factors, such as environmental conditions, changes in temperature, water usage patterns, or the presence of blockages in the plumbing system. Identifying and addressing the underlying cause will help eliminate the odor permanently.

How do I fix the sewer smell in my house?

To fix the sewer smell in your house, you need to identify and address the specific cause. Start by checking for dry P-traps and running water in unused fixtures to refill them. Inspect and clean vents regularly to ensure proper airflow. If you suspect sewer line damage, contact a professional plumber for inspection and repairs. Clear clogged or blocked drains using a plunger or drain snake, and consider using drain cleaners or professional assistance for stubborn blockages. For major issues like sewer line backups or sewer gas leaks, it’s advisable to seek professional help.

Will sewage smell go away?

The sewage smell will not go away on its own if there is an underlying issue. It’s important to identify and address the cause to eliminate the odor completely. By following the appropriate steps and seeking professional assistance when necessary, you can effectively get rid of the sewage smell in your house.

Is breathing sewer gas harmful?

Breathing sewer gas can be harmful to your health. Sewer gases, such as hydrogen sulfide, methane, and ammonia, can be toxic and may cause various health issues. Prolonged exposure to these gases can lead to symptoms like headaches, dizziness, nausea, respiratory problems, and eye or throat irritation. It’s important to take the necessary precautions and address any sewer gas issues promptly to protect your health.

Is sewage smell toxic?

Sewage smell itself is not inherently toxic. However, it can indicate the presence of harmful gases and bacteria that can be harmful to your health. The sewage odor is a warning sign that there may be issues with your plumbing system, such as leaks, backups, or damaged pipes, which can lead to the release of toxic gases. It’s crucial to address these issues promptly to prevent any potential health risks.

Can sewage make you sick?

Exposure to sewage can potentially make you sick. Sewage contains harmful bacteria, viruses, and other pathogens that can cause illnesses such as gastrointestinal infections, respiratory infections, skin infections, and other health issues. It’s important to avoid direct contact with sewage and to address any sewage-related problems promptly to minimize the risk of illness.

How do you detect sewer gas?

Detecting sewer gas requires a combination of observation and professional assistance. You can start by identifying any foul odors that resemble a sewage smell in your house. Additionally, look for signs of plumbing issues such as leaks, dampness, or water stains. However, to accurately detect and diagnose sewer gas issues, it’s recommended to consult a professional plumber or sewer odor specialist who can use specialized equipment to locate the source and provide appropriate solutions.

Why does sewer smell come and go?

The intermittent nature of sewer smell can be attributed to various factors. Changes in environmental conditions, such as temperature and air pressure, can affect the movement of sewer gases and the strength of the odor. Additionally, blockages or obstructions in the plumbing system can cause the smell to fluctuate as water usage and pressure change. Identifying and addressing the specific cause will help eliminate the intermittent sewer smell and ensure a consistent and odor-free environment in your house.


Don’t let the sewage smell in your house come and go without taking action. It’s essential to address the issue promptly to ensure a healthy and comfortable living space. By understanding the possible causes behind the odor and implementing the solutions we’ve discussed, you can bid farewell to those unpleasant sewage smells for good. Remember, if you’re unsure or unable to resolve the issue yourself, don’t hesitate to contact a professional plumber who can provide expert assistance. Here’s to a fresh and odor-free home!

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