How to Increase Bacteria in Your Septic Tank Naturally Using Household Products

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Woman using kitchen sink to wash her hands
Photo: Luis Alvarez / DigitalVision / Getty Images
Jenna Jonaitis
Written by Jenna Jonaitis
Contributing Writer
Updated May 7, 2024
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When bacteria levels in your septic tank are low, you can experience backups in your septic system, which can be hazardous (and smelly). Without bacteria to break down the solid waste, the tank fills up more quickly and the pipes can get clogged. Learn how to increase the bacteria in your septic tank naturally with rotten tomatoes or yeast. The best part? Boosting the bacteria takes five minutes or less. 

Why Increase Bacteria in Your Septic Tank Naturally?

The natural bacteria in your septic tank breaks down solids, helping ensure your tank doesn’t become full too soon. Natural bacteria also help ensure your septic tank's health and balance pH levels. Without enough natural bacteria, you’re more likely to experience clogs or the need to pump your septic tank more often than usual. 

How Much Does It Cost to Pump Your Septic Tank

The cost to pump a septic tank ranges from $250 to $550. You can avoid additional pumping by maintaining healthy bacteria in your septic tank. Most septic tanks need to be pumped once every three to five years to keep everything running smoothly.

Signs You Need More Bacteria in Your Septic Tank

If bacteria levels in your septic tank are too low, you may experience:

  • Your tank filling up sooner than every three to five years

  • A septic or rotten egg smell outside of your home or coming from your drains

  • Slow-draining toilets and sinks

  • Backed-up drains and toilets

  • Lush, green grass near your tank or above the septic lines

  • Standing water in your yard

How to Increase Bacteria in Septic Tank Naturally

Two main ingredients can increase the natural bacteria in your septic tank: rotten tomatoes and yeast. Rotten tomatoes are known to work better than yeast, but adding yeast may also help. Septic tank experts recommend avoiding septic tank additives, as they can harm your system more than help it. 

1. Add Rotten Tomatoes Through Your Garbage Disposal

Tomatoes on the vine sitting on kitchen counter
Photo: Joanne Liu / Moment / Getty Images

Decaying tomatoes can increase bacteria in your septic system by breaking down pectin and plant cell walls.

Buy three rotten tomatoes and allow them to go past their prime. Put them in your garbage disposal one at a time and run the water while you run your garbage disposal. Allow the garbage disposal to process the tomatoes and pass them through fully. You can add rotten tomatoes to your septic system every three months as needed.

2. Flush Yeast Down Your Toilet

Some experts recommend adding yeast to your septic system to increase enzyme health in your septic tank. Whether yeast increases bacteria is debatable, but it won’t harm your septic system. 

Pour 1/4 ounce of dry baking yeast into your toilet and flush. You can do this once every three months or up to once per month. Avoid adding extra yeast to your septic system, though, as it can cause frothing. The additional gases from the yeast can keep solid waste from settling to the bottom. When the sludge doesn't settle, clogs and slowdowns can happen.

Tips for Maintaining a Healthy Septic System

To allow the bacteria to work properly, ensure you take care of your septic system. Proper maintenance prevents backups, clogs, and malfunctions.

1. Dispose of Waste Properly

Sending grease, fats, trash, feminine hygiene products, wipes, and cat litter down your drain or toilet can cause major backups and clogs. Place these items in the trash instead. 

Harsh chemicals and bleach can kill the organisms in your septic system that break down solid waste, so be sure to safely dispose of them elsewhere.

2. Conserve Water

Man taking clean dishes out of the dishwasher
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Reducing the amount of water your home uses can lower the chance of a septic tank backup. Conserve water by limiting the length of your showers, using a dishwasher, and choosing low-flow fixtures.

3. Landscape Appropriately

Placing plants with deep root systems near your septic system can disrupt your drain field. Work with a local septic tank pro to decide on the right septic tank landscaping.

4. Use Natural Soap and Cleaning Products

Switch to natural cleaning products and soap, as chemicals, bleach, and antibacterial soap can kill the bacteria in your septic tank. 

5. Dispose of Medicine Elsewhere

Woman taking medicine bottle from the cabinet
Photo: Comstock Images / Stockbyte / Getty Images

Flushing antibiotics and prescription medicines down your drain or toilet can harm the bacteria in your septic tank. Dispose of your medicine properly through a pharmacy or hazardous waste facility.

6. Don’t Use Septic Tank Additives

The EPA does not recommend using chemical additives in your septic tank. Most septic systems do not need additives to work correctly and can decrease your drain field’s performance. Before trying septic tank additives, consult with a local plumber or septic tank pro.

7. Have Your Septic System Inspected

Man removing septic tank cover to inspect the tank
Photo: Natalia Kokhanova / iStock / Getty Images Plus / Getty Images

A licensed professional should inspect your septic system every three to five years. They assess the health of your septic system and fix any issues with your pump, tank, or drain field. The cost of a septic inspection ranges from $200 to $900.

8. Pump and Clean the System

A licensed professional should pump your septic tank once every three to five years. A pro safely empties your septic tank system, helping to prevent backups and overflows. The average cost of a septic tank pumping is $400.

DIY vs. Hiring a Pro 

You can increase the bacteria in your septic tank with rotten tomatoes or yeast without the help of a pro. Unclogging a septic tank or pumping your septic tank is a different story. These tasks can be challenging and messy. It’s best to hire a local septic tank cleaner to assess the situation, unclog or pump your tank, and make recommendations to prevent future issues. Unclogging a septic tank costs $400 on average.

Frequently Asked Questions

You can replenish good bacteria in your septic tank by adding three rotten tomatoes or 1/4 ounce of yeast every three months. Put three overripe tomatoes in the garbage disposal while running the faucet. Or pour 1/4 ounce of yeast in the toilet and flush it down. These are the best natural ways to increase bacteria in your septic tank. Septic tank additives are not necessary and may even cause harm to your septic system.

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Learn more about our contributor
Jenna Jonaitis
Written by Jenna Jonaitis
Contributing Writer
Jenna Jonaitis is a professional freelance writer with over seven years of experience. She covers wellness, parenting, and lifestyle topics.
Jenna Jonaitis is a professional freelance writer with over seven years of experience. She covers wellness, parenting, and lifestyle topics.
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