Septic tanks

septic tank Septic tanks are an alternative treatment of wastewater compared to sewer. Septic tanks are often used in rural areas such as the North Georgia Mountains in order to deal with the small amount of sewage created by a single household. The septic tank is part of a septic system. The way the septic system works is one line will enter the tank on one end and exit on the other. By the means of bacteria breaking down the solids, almost everything turns into a liquid. The liquid then flows into the drain field and is absorbed into the groundwater and is cleaned naturally. There is only a little sludge that sinks to the bottom of the tank and stays there. It’s almost like sand.


The supernate from a septic tank is not as clean as the water released by wastewater treatment plants.  This supernate would pollute streams and the groundwater if it came in contact with them before trickling down through the soil.  As a result soil permeability must be carefully tested before installing a septic system. The term permeability refers to how easily water can trickle down through soil. Septic systems do not work well in clay soils since clay is a relatively impermeable soil and does not allow the supernate to soak in.  So if a septic system is installed in clay soil the supernate often rises to the surface of the ground producing a very unsanitary situation.  The Health Department has established soil testing procedures which must be followed before a septic tank can be installed.  These procedures test the permeability of the soil.  The procedure is outlined below:

1. A 2 feet deep hole is dug in the soil.

2. The hole is saturated with water.  Then the hole is filled with water to a known depth.

3. The water is allowed to sink into the soil for 30 minutes.

After 30 minutes the depth of the water in the hole is then measured. Once the soil has been tested and the Health Department has issued a permit the septic system can be installed. The first factor to be considered when you are ready to install is the size of the tank.  The size you need depends upon the size of the family and the type of use.  For example a larger family will create more waste and will require a larger tank. Households which use their tanks for garbage disposal will also require a larger tank. The amount of available land will also influence which tank size is chosen.

In non permeable soil up to 60% of the water can come to the top of the ground and will be dispersed through transpiration or breathing of plants.  The other 40% will become groundwater.

The last consideration when installing fill lines is that the supernate must be distributed evenly across the ground. When the ground is sloped  then the lines should be connected in parallel or in series to provide efficient removal. The lines should also be placed so that they are perpendicular to the slope of the land.  Another way of saying this is that the fill lines should be parallel to the contour lines of the land.


The need for only minimal maintenance is one of the major benefits of having a septic system. Preventing plant growth on the septic field is the most intensive maintenance required after installation. Trees must not be allowed to grow over your septic tank system as the leaves can clog the septic lines. Grass must be mowed above the septic field.  This prevents brush and small plants from growing in the field as the plants could sink their roots down into the septic lines and break them. Also don’t allow anyone to drive or operate heavy machinery over any part of the septic system and don’t build anything over the septic field. Good septic system operation and maintenance include conserving water, being careful that nothing harmful is disposed of through the system, and having the system inspected annually and pumped regularly. By educating everyone in your household about what is and what isn’t good for septic systems you can begin to develop good maintenance habits.

What is harmful

What you put into your septic system can greatly affect its ability to to its job properly. Remember that your septic system contains living bacteria that digest and treat waste. As a general rule do not dispose of anything in your septic system that can be just as easily put into the trash. Your septic system is not designed to be a trash can and solids can build up in the tank and will need to be pumped. The more solids that go into the tank the more frequently the tank will need to be pumped and the higher the risk for problems to arise.

In the kitchen avoid washing food scraps, coffee grinds, and other food items down the drain. Grease and cooking oil can contribute to the layer of scum in the tank and should also not be put down the drain.

The same approach used in the kitchen should also be used in the bathroom. Don’t use the toilet to get rid of plastic, paper, towels, facial tissue, tampons, sanitary napkins, cigarette butts, dental floss, diapers, kitty litter, etc. The only things that should be flushed are waste-water and toilet paper.

When used as recommended by the manufacturer most house hold cleaning products will not affect the operation of your septic system. Drain cleaners however are an exception to the rule and should not be used as they can kill the bacteria and disrupt the operation of the septic tank. Cleaners such as bleach, disinfectants, and toilet bowl cleaners are ok as long as they are used in moderation and in accordance to the product label.

In order to avoid permanently damaging your septic system do not dispose of hazardous household chemicals such as paint, varnish, paint thinners, oil, anti-freeze, pharmaceuticals, antibacterial soaps, gasoline, pesticides, etc. Even a small amount of these chemicals can destroy the helpful bacteria and pollute the ground water. If you need to wash paint or stain from brushes and rollers squeeze out all the excess paint on several layers of newspaper and get as much out as you can before rinsing.

While many products out there claim to help septic systems work better the truth is that most engineers and sanitation professionals believe that commercial septic additives are at best useless and at worst harmful to your system. There are two types of additives: biological (bacteria, enzyme,and yeast) and chemical. Biological additives are harmless but some chemical additives can harm the soil in the septic field and contaminate the ground water.


A few appliances can also harm your septic system. They are garbage disposals, hot tubs, and water softening systems .

Garbage disposals can increase the amount of solids in the tank up to 50% and should not be used at all. Because a garbage disposal grinds kitchen scraps into tiny pieces once they reach the septic tank they are suspended in the water and get pumped out with the liquid waste into the soil. It also significantly increases the amount of sludge and scum in your septic tank. Many states require a larger minimum size tank if there will be a garbage disposal in the house.

Hot tubs are very common to have today and while the soothing waters may be good for your body the large amount of water that drains from the hot tub is harmful to your septic system. Emptying large amounts of water into your septic system can cause an overload, stir the solids in the tank causing them to be pushed out into the septic field, and eventually cause the system to fail. Instead of draining the water into your septic system the hot tub water should be cooled and drained on to grass or other areas of your yard away from the septic system.

Some water softening systems pump hundreds of gallons of water into the septic tank all at once. This again can stir the solids in the tank causing them to be pushed out into the septic field, and eventually cause the system to fail. Water softeners also remove the hardness by using a salt to initiate an ion exchange. This flushes pounds of used salt into the septic system and can affect the digestion in the tank and reduce the permeability in the soil of the septic field. If you are going to use a water softening system you should have alternative routing installed.

Feel free to contact us with any questions or concerns you may have about installing or maintaining a septic system.

C&H Construction is a licensed general contractor and Custom Home builder located in Blairsville, Union County Georgia serving Towns County Georgia, Fannin County Georgia, Gilmer County Georgia and the North Georgia Mountains.