Your septic tank provides a vital function, and acts as the storage location for all of the plumbing waste that is produced in your home. However, over time due to age and wear, and due to the very nature of the job that your septic tank performs, it is possible for the smell of sewage to back up into your bathroom. Thankfully, there are a number of things that you can do to remove the unpleasant odor.
Baking Soda and Vinegar
As a general rule of thumb, you should flush a cup of baking soda mixed with a quarter cup of vinegar down your toilet or sink periodically. This mixture will help neutralize the smell of sewage that is seeping up from your pipes while still maintaining the bacterial balance of your septic tank. While the exact rate at which you should flush this solution down your toilet depends on the amount of use that you get out of your septic tank and how bad the odor is, as a general rule of thumb you should deodorize your plumbing at least once a month.
Check the Vent
Your septic tank has a vent installed that is designed to regulate the pressure of your septic tank while also allowing the gases from your septic tank to vent themselves slowly over time, usually at a rate that is too slow for you to notice with your nose. However, if the vent has become blocked due to organic debris or another blockage, the gases in your septic tank will have nowhere else to go but into your home, which is what is causing that unpleasant smell. Check the vent to see if there is anything blocking the airflow: leaves, sticks and other organic matter is the most common culprit, though ice and snow can have the same effect.
If the above two points were ineffective, you should contact a professional plumber to come in and take a look at your septic tank. Often, bad odors in your home are caused by your septic tank backing up, which can be because of physical damage to the tank or a lack of maintenance. If your septic tank is full, there is nowhere for the waste to go: if you are experiencing odor with sewage backup, the problem likely lies with the tank itself, and you will need to call a plumber to have it emptied.