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How Do I Increase Good Bacteria in My Septic Tank?

Bacteria are an essential part of a septic system. They help break down organic matter in wastewater, making them one of the most important parts of a septic system. Without these helpful bacteria, the septic tank would not be able to absorb or biodegrade solid waste.

Vital Bacteria

Bacteria are single-cell microorganisms with no nucleus, present in most habitats on the planet and in the bodies of plants and animals. In septic systems, bacteria are one of the main microbes that help process the wastewater, though fungi, algae, protozoa, rotifers, and nematodes can also be found.

Septic tanks rely on the natural process of bacterial decomposition to break down and treat wastewater. Bacteria within the tank initially break down organic materials, such as food scraps, toilet paper, and soap scum. This process helps reduce solids and other contaminants that can block pipes or otherwise disrupt a septic system.

Bacterial populations then continue to feed on these substances, breaking them down further into their component parts before they are released into the environment. The bacteria oxidize nitrogen and carbon compounds in the waste, increasing its pH level and making it more stable for use beyond the tank.

What Is the Best Septic Tank Bacteria?

Given the importance of bacteria to a septic system, homeowners often look for options they can purchase to keep them healthy and thriving. Many people are enticed into purchasing additives that claim to enhance bacterial populations in the tank, but it is important to be aware that most septic professionals – and even the US Environmental Protection Agency – do not advise using them.

Even though commercially sold additives may be “approved” for use with septic systems, there is no peer-reviewed scientific literature that supports their claims of effectiveness. In fact, some additives may even be harmful to septic systems.

The best septic tank bacteria are naturally occurring and supplied by the wastewater entering the tank. Simply practicing adequate maintenance of their tanks and following basic septic guidelines is enough to ensure that there is enough bacteria to break down solids, waste, and other contaminants.

Forget the Additives!

Instead of using additives, there are some common-sense things that homeowners can do to keep their septic system functioning effectively.


Avoid the use of harsh cleaning chemicals, like bleach, as they can harm the bacteria in the septic tank. Chlorine, bromine, formaldehyde, phenols and other chemicals found in household cleaners also can kill septic tank bacteria. These chemicals can disrupt the natural breakdown process of organic waste and create a buildup of solids that can cause blockage or other damage to your septic system. If using chemical cleaners for tasks such as toilet cleaning, try to select a brand that is specifically designed for septic tanks.

Fats, Oils, and Grease

Do not pour grease or oils into your drain. Fats, oils, and grease (also known as FOG) can be dangerous to septic tank bacteria because they form an impenetrable layer over the surface of the water in the septic tank. This layer prevents oxygen from entering the system, which is necessary for bacteria to survive. Additionally, since FOGs are not biodegradable they can clog pipes, promote sludge buildup, and cause blockages in the pipes or septic drain field.

Medications and Anti-Bacterials

Antibiotics and anti-bacterials (e.g., soaps, gels, cleaners), by design, kill bacteria. Septic system owners should avoid introducing them into the septic system by pouring them down the drain.

However, it is not just the obvious bacteria killers that can be harmful; it is best to avoid flushing any medication – prescription or over the counter. Even those not specifically identified as anti-bacterial can kill or impede the effectiveness of the beneficial bacteria in a septic tank. The best option for disposing of medications is to take them to a local pharmacy or drugstore that has a medication disposal program. Alternatively, you can check with your local waste management agency for information on how to safely dispose of any unwanted medications.

Use Water Judiciously

Limit long showers and laundry loads to prevent overloading the tank with water, and consider installing low-flow fixtures like toilets, shower heads, and faucets. Using too much water can be harmful to septic tank bacteria because the high level of water can overwhelm the system and reduce the amount of oxygen necessary for bacterial growth. Additionally, a sudden influx of water into the septic tank can displace solids that were being broken down by bacteria, increasing sludge levels and causing blockages.

Be Cautious About What Gets Flushed

Avoid flushing non-biodegradable items such as facial tissue or sanitary products. These can harm septic tank bacteria by preventing the breakdown of organic materials. These items are too dense for bacteria to digest, meaning that they will remain in the system and eventually clog pipes or form impenetrable layers on the water surface. This will obstruct oxygen from entering the system, which can kill beneficial bacteria that would otherwise keep the septic tank functioning properly.

Have Regular Septic Tank Services

Keep to a regular schedule of septic tank pumping, and have your entire system inspected regularly by a septic professional. A septic professional can tell if septic tank bacteria are working properly. They will first use an inspection camera to view the inside of the tank and check for signs of blockage. After that, they will test the water in the tank to measure oxygen levels and the number of viable bacteria present. If these values are within normal ranges, it is likely that bacterial activity is healthy.

regular septic tank pumping

One Caveat – Professionally Recommended Additives

Occasionally, a septic system may be so out of alignment that a septic professional may recommend biological additives that are not hazardous to the environment or the local water supply. However, because these substances can be dangerous if used improperly, they should only be used under the guidance of a professional septic company near you. 

Septic Service In and Near Lakeland

At Septic & Drainfield Depot, we understand the importance of ensuring septic systems are functioning properly. That is why we offer services to inspect and test septic tanks, so that homeowners can rest assured that their systems are running at optimal levels.

With our commitment to providing quality service and expertise in septic systems, homeowners and commercial property owners alike can trust us to keep their septic systems healthy.

When you need a septic company in and near Lakeland, contact the best in Septic & Drainfield Depot.

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With our transparent pricing, free estimates, and honest professionals, our company shines above the rest in Lakeland, FL. We are committed to finding out the issue the first time we walk foot on your property, and finding an effective and efficient solution that will fit within your budget. A septic problem is never something anyone wants to deal with, but we are ready to tackle anything you need. Contact us for a free estimate.