My Septic System Smells

Does Your Outside Septic System Smell Terrible?

Your septic tank is a large, waterproof, concrete tank in the yard of your home. The septic tank collects wastewater that has been flushed down drains, showers and toilets. Inside the septic tank sits a layer of sludge on the bottom, scum on top, and relatively clear water sandwiched between.

With all that bacteria, grease and other waste from your home buried on your property, you’ll probably notice a variety of smells coming from your septic system over time. Some of these odors are expected, but in general, your septic system should not fill your house with a scent. If you do notice a smell, there are a variety of ways to handle the problem on your own.

Dried Out P-Trap


Your home is connected to the septic tank through a network of pipes. Water trapped in the pipes prevents the odor from the septic tank from backing up into your home. Sometimes, usually in unused bathrooms or utility rooms, this water dries up and smells from the septic tank enter the home. If this occurs, the solution is simple: add water to the pipes.

  1. Shine a flashlight into all the floor drains and sink drains in your home. Look for signs of water inside the drains.
  2. Dump 2 quarts of water into any drains that appear to be dry.
  3. Run any showers, sinks or toilets that you don’t commonly use.

In the future, you can prevent the P-traps in your drains from drying out by periodically running all showers, sinks and toilets, and by regularly dumping water into any floor drains.

Clogged Vent Pipe

Clogged Vent Pipe

The plumbing vent is a pipe that connects to your plumbing and exits through the roof of your home. The vent pipe equalizes the pressure in your pipes and prevents a variety of problems from occurring (this includes gurgling toilets, dried out P-traps, smells and more). This vent can easily become clogged with falling debris, tennis balls and even dead birds.

To unclog the vent pipe, you’ll need to climb onto the roof your home. Do not attempt to do this alone or without taking proper safety measures.

Once you’ve gained access to the opening of the vent pipe on the roof, there are two standard ways that a homeowner can unclog the pipe.

Snake the pipe. Not all homeowners own drain snakes, so this isn’t an option for everyone. Drain snakes are available for sale at home improvement stores. Professional-grade snakes are also available to rent.

  1. Look inside the vent pipe and clear out any debris within easy reach.
  2. Insert the snake into the vent pipe. Push the snake into the pipe until it reaches the clog.
  3. Remove the snake when the clog has been dislodged.

Pour water down the pipe. If you don’t own a drain snake, you can also use water from a hose to dislodge the clog. The weight from the water will push the clog out of the vent pipe.

  1. Run the hose into the vent pipe.
  2. Have a partner turn on the hose from the ground.
  3. Listen for the whooshing noise as the weight of the water pushes the clog out of the vent pipe and the pressure inside the pipes equalizes once again.

There are many resources online that homeowners can turn to for more information about septic systems and how to prevent and stop odors, including this detailed article about the many reasons why odors occur both indoors and out.

What problems have you encountered with your septic system? How did you solve the problem? Leave a comment in the box below. We’d love to hear about your home remedies and solutions to these common problems.

4 thoughts on “Does Your Outside Septic System Smell Terrible?”

  1. Shayna says:

    We have lived in our late 1970’s built home for 3 years now and have smelt a terrible smell on certain days when there is a breeze outside. We thought this was due to the old, unsealed lids on our septic system. This summer we had to have a new pump installed and we also had a nice sealing lid system put on hoping that would solve the smell. Well, it did not. Our septic company told me to try Brewers yeast and see if that helps and said the only other thing is that the smell could be coming from the roof pipes but never suggested they may be clogged? We are desperate to figure out where this smell is coming from? We have a few neighbors as well but it seems to be coming from around our house. Sometimes we smell it by the tanks and others around the house in the front yard. Any thoughts would be so appreciated.

  2. Troy Fleming says:

    I have I think the same problem. It smells outside near the tank. Did you receive any good solutions for your problem?
    Thank you Troy

  3. Millie Hue says:

    Thanks for pointing out that the house must never be filled with the scent of the septic system. With that in mind, I guess I have to hire experts to work on our system. It just woke me up in the middle of the night yesterday. The scent reached our bedroom on the second floor already.

  4. T says:

    Did you ever find a way of resolving the smell outside??

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