5 Causes of Septic Tank Odor

A septic tank outside.

Septic tank odor is a common problem in septic tanks. This problem happens when gases that are supposed to escape get redirected back into the house. It will affect the quality of a person’s life if the odor starts seeping into the house. Septic tank odor problems must be dealt with immediately because some of the odors contain toxic gases like methane. There are many causes of septic tank odor. These are the five most common causes.

1. Dry Drains

Dry drains are one of the top reasons why there is an odor in the house from a septic tank. All septic tanks have a trap component in the pipe. The function of this U-shaped pipe is to make sure that gases don’t seep through by blocking it with water. However, sometimes the water dries and gasses begin to seep into the house. This problem usually occurs in places like the bathroom. A plumber can help you clear the drains.

2. Cold Weather

Cold weather is another culprit for strong septic tank odor. During extremely cold temperatures, ice and frost can develop around the plumbing vent and block the vent. When such blockages occur, the sewer gas will be redirected back into the home. Check the plumbing vent during winter to ensure that this problem does not occur.

3. Surface Runoff

This problem can happen during high rainfall. Groundwater or surface runoff can occur, and the tank gets over flooded. To solve this, provide an intercept drain to contain the excess water.

4. Faulty Tank Vent

A man works on a septic tank.

Sometimes when a house gets renovated, the old septic tank will get blocked or will be covered up. If the room that was previously used to vent the gas has been transformed into something else, the room will stink like the sewers.

All septic tanks have a tank vent installed. The function of the vent is to allow gases to escape from the sewage, preventing toxic and flammable buildup in the vent. Anything could cause the vent to clog up, like frost, animals, or hardened waste.

Another problem that can occur with the vent is the vent stacks. Gases that are released by the tank are released by a pipe called vent stacks. The vent stacks sometimes can become clogged with leaves. When the vent is clogged, gases will be redirected back into the house. There also have been cases where strong winds blow the gases back in, but that is a rare occurrence. To solve this problem, raise the height of the stack.

The final problem, and one that should not occur, is that the mechanic forgets to install the vent itself. This should not be a problem if a reputable company was hired to do the job.

5. Septic Tank is Full

This is a very common problem and one that is easily solved. Too must waste in the tank results in the tank getting clogged. As long as there is regular pumping, this problem should not occur.