4 Reasons For Foul Odor After Septic Tank Pumping

Our discussion here will focus on the causes of foul septic tank odor after pumping.

Septic tank pumping is an important maintenance activity that needs to be carried out every 3 to 5 years. Some homeowners stick to a pumping schedule while others don’t.

When ignored, a septic tank may exceed its scheduled pumping date and development issues.

Common issues include odor and backups among others. Normally, routing pumping tasks should help solve the problem. However, this isn’t always the case as septic tank odor persists long after the tank has been pumped.

What could be the cause of this odor? The right answers are needed to fix any unforeseen or lingering issues once and for all.

More than Just an Odor

Septic tank odors emanate from gases that are by-products of bacterial breakdown of waste products.

These gases include hydrogen sulfide, methane, carbon dioxide, sulfur dioxide, ammonia, nitrogen dioxide, and carbon dioxide (in traces).

Among these gases, hydrogen sulfide is the most perceivable and is identified by its characteristic rotten egg smell. When perceived in small amounts, septic tank odors won’t pose a significant danger.

However, you’re likely to experience certain symptoms in cases of mild exposure to septic tank gases. These include fatigue, headaches, vomiting or nausea, lightheadedness or dizziness, and poor memory and concentration.

It’s also possible for you to be exposed to high levels of septic tank odor or gases. You should try as much as possible to avoid such as it could be fatal.

Symptoms include loss of smell, lung, mouth, and throat irritation, as well as pink eye and eye irritation.

Other fatal symptoms include seizures, coma, and sometimes death. The farther you stay away from a strong septic tank odor, the better.

What Causes Septic Tank Odor After Pumping

A septic tank is normally expected to release an offensive odor when it’s being pumped. However, when such odor persists long after pumping is completed, it becomes a problem that needs to be addressed.

There are several possible reasons why your septic tank smells after pumping. These likely reasons include malfunctioning plumbing vents, natural air circulation; spillage caused by pumping, and damaged toilet seal.

Here is why a house smell like septic after a tank pump? Let’s briefly discuss each of these points as follows;

  • Malfunctioning Plumbing Vents

Plumbing vents are important components of the system designed to channel sewer gas away. These are usually directed upward and away from your surroundings to help eliminate awful septic odors.

However, such vents begin to malfunction when frozen or clogged.

What happens is that sewer gas hardly has an escape point, thus leading to uneven pressure within your septic system. Even when your tank is evacuated or pumped, such plumbing vents remain blocked or clogged.

As such, septic backups resulting from uneven pressure generate strong odors that permeate your home.

Here, you can see that it’s not enough to have your septic tank pumped. In other words, pumping your septic tank alone won’t address other underlying issues.

All malfunctioning plumbing vents will need to be fully resolved or fixed. The services of a plumber will be required here.

  • Natural Air Circulation

Natural air circulation normally happens after a septic tank is pumped.

With the waste content of the tank gone, what’s left is a system full of gases. These gases are known to produce such odors. Now, gases will naturally find any openings to escape.

Drains with dried-up water barriers provide ready openings for such gases to escape through. You may want to remedy the problem by running water through every drain in your home. This helps restore the protective barrier that shields such gases from entry.

Sometimes, this remedial action won’t give many results as septic tank odors may still linger. Whether the odor is a bit reduced or remains strong proceed to check where the odor is most present.

Being able to pinpoint the problem enables you to fix it as early as possible.

  • Spillage Caused by Pumping

Septic waste spillage is a possibility when a pumping job isn’t neatly and carefully done.

However, no matter how the job is carefully done, accidental spills are possible. This means the spillage of sewage matter or septic waste on your property. This can be quite gross and results in a lot of foul odor.

Who you call for the job also matters. Some septic service providers aren’t professional enough and may mess up your property with septic waste. It’s important not to perform the cleaning yourself.

When you notice such spillage, ensure they return for cleanup or call other septic providers if you can’t reach them. Cleaning up septic waste spills is quite hazardous due to the harmful bacteria found in them.

This is a possible reason why you’re perceiving septic tank odors. You might want to further check around to determine if there are other septic waste spills.

Carrying out this activity ensures you identify all possible sources of the foul odor to have them cleaned up.

  • Damaged Toilet Seal

All toilets are connected or held tightly to the floor using airtight rings or wax seals. These are airtight to help prevent the escape of septic tank gases into the home.

When this seal is compromised, it easily leaks out such gases. This makes your home smell awful.

To have it fixed, you’ll need to identify where such odor is coming from. Once identified all a plumber for repairs. In the course of repairs, a plumber will further inspect any possible sources of odor you may have left out.

When such additional leakage points are found out, they’re fixed.

To have your home’s surroundings permeated by septic tank odor after pumping isn’t a good situation at all. When such is perceived long after pumping, it’s as a result of one or more of the factors mentioned above.

Urgent solutions need to be found.


Septic tank odor after pumping can be addressed by adopting some preventive actions as mentioned above.

All of these maintenance actions are geared towards making your septic tank odor-proof. Such odors are meant to only escape through the vent provisions made available.

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