Boston Home Inspection, Inc.

Boston Home Inspection, Inc.
8930 Snow Hill Road
Ooltewah, TN 37363
(423) 802-9935

Septic Tank Maintenance
Facts and Folklore


The folklore of septic systems could probably fill a small book. Like most folklore, the stories reflect elements of truth, ignorance, and humor. The purpose of this pamphlet is to dispel some myths about septic systems and explain how they actually work. Hopefully, this information will help you keep your system working well for many years.

How the system works

The septic system is a natural sewage treatment and disposal system. By natural, we mean that it relies on bacteria to digest and clean the wastewater. The bacteria in the septic tank literally eat the solids in the tank turning them into liquids and gases. As you might expect these gases have a foul odor. To avoid these bad odors they are vented off through pipes on the house roof. The liquid wastes flow to the drainfield. The final purification occurs by organisms living in the soil.

The bacteria in the septic tank eat and digest most of the waste. But there's always some waste that doesn't even appeal to these critters. As a result, the health department recommends pumping out the tank every three to five years. This will remove excess sludge that has accumulated.

Common myths - dead cats and a pound of yeast

Theories abound about the best way to startup a new septic system. Most theories deal with "seeding" the septic tank to get good bacterial growth started. Advice has ranged from flushing a pound of yeast into the system, to seeding the septic tank with manure, all the way to placing a dead cat in the septic tank. The Health Department doesn't recommend any of these.

Starting a new system

Most of this folklore is believable because it contains elements of truth. The concept of seeding a septic tank is partially true. Septic systems are biological systems and must have bacteria to work. However, no special seeding is necessary to get them started. The simple act of using the system will provide all the bacteria necessary to make the system function well. Yeast, manure, and especially dead cats will not help develop the colony of bacteria in the tank any faster.

Additives for old systems

Septic system folklore doesn't stop with seeding a new septic system. Many products are sold that claim to make old systems like new. Other products claim to eliminate the need to pump out the septic tank. These products usually contain yeast, bacteria, enzymes, or chemical degreasers.

People often ask if additives can reduce or eliminate the need to pump a septic tank. It's a good question, too. So far, no additive has been proven effective in a controlled scientific study.

Why additives don't work?

Some of the solids in the tank are sand, grit, bits of plastic and similar materials. No enzyme or bacteria can digest these. Other organic solids are not very digestible. Hence they accumulate. Bacteria that are added must compete with bacteria that are adapted to living in your septic tank. These adapted bacteria have the home field advantage. The newly added organisms can't compete and become dinner for the resident organisms. Enzymes on the other hand are not living and cannot reproduce. Whatever is added to the tank is all that will ever be there. Most septic tanks are 1,000 gallons or larger and the quantity of enzymes added are too low to be helpful.

In short, adding enzymes or bacteria usually won't cause a problem but they won't help either. The solution is simple. Pump your tank every three to five years. This solution is easy, safe, and often cheaper than buying septic tank additives.

The routine maintenance of pumping your tank.

After a system is working it requires very little maintenance. About all you have to do is pump the tank out every three to five years. The purpose of pumping out the tank is to remove accumulated solids. These solids can and will stop-up the soil where the wastewater is to be absorbed. When you have your tank pumped, it is wise to inspect the condition of the tank. Your licensed septic tank pumper can check the condition of the septic tank and the pipes going into and out of the tank.

The most often heard myth though is the concept that, "I never had to have my septic tank pumped before." This reflects an unfortunate attitude of neglect. Another way of looking at is, "If it ain't broke don't maintain it." The health department certainly doesn't promote this attitude. We prefer to think of it like changing the oil in you car. It's always wiser to do before you have to and the system stops working.

Call the Department of Health with your questions

If you have a question about your septic system, or suspect a problem, call your local health department environmental health specialist. They are trained and knowledgeable about septic systems. They are here to serve you and can offer free, independent, and professional advice.


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