Your Septic Tank System
If your home is not connected to the public sewer system, all the wastewater your home generates is treated by an “Individual wastewater treatment system”, commonly called a septic system.
Every time that anyone in your home uses water, the wastewater that is generated as that water goes down the drain is treated in your own yard, on your own property! Just think, every time anyone washes their hands, washes the dishes, runs the clothes washer, takes a shower, or flushes a toilet, all that wastewater needs to be cleaned and returned to the environment.
It is the job of your septic system to clean the wastewater and re-introduce the treated water back into the ground and environment.
It is your job, as a homeowner, to understand how your septic system works and what you must do to maintain your system.
What Is a Septic Tank System?
If you are like most people, you know very little about your septic tank system. This is understandable because there have been many myths and misconceptions surrounding septic tank systems and the way they work. Here, we will try to give you a clear understanding of what happens to your household waste after it goes down the drain. As the diagram illustrates, wastewater generated in your household travels outside into the septic system. The most common type of septic system consists of two parts. 1. The septic tank and 2. the leaching system. Some more complicated systems may include aerators, pumping stations, dosing chambers, drop boxes, raised fill leaching systems, or other alternate systems.
The soli pipe that leaves your house empties first into the septic tank.
The Septic Tank
The septic tank is a large box that is more commonly made out of precast concrete. Some septic tanks are made of metal or plastic. The size of a residential septic tank depends on the number of bedrooms in the home and the regulations in the county in which it is installed. Typically, a three bedroom home will have a 1250 gallon septic tank and a four bedroom home will have a 1500 gallon septic tank. Smaller homes and older homes may have a 1000 gallon septic tank, or even a smaller tank. While older tanks consist of a single compartment, newer tanks often have two compartments. Some homes have more than one tank. When household waste enter the tank, several things occur:
- Everything flows into the tank through the inlet baffle and into the middle section of the tank. Here, the bacteria that live in the tank break down the wastes and it separates.
- Three layers form in the middle section of the tank. Organic solids form a crusty layer of “scum” at the surface of the rank. Inorganic solids form a layer of “sludge” at the bottom of the tank.
- The middle layer is relatively clear liquid called “effluent“.
The main purpose of the septic tank is to provide a place for all the solid wastes that leave your house to accumulate. Here the solid wastes can be dealt with by pumping them out of your system. Solids overflowing beyond the tank and into the leaching system should be avoided at all times. Solids overflow from the septic tank when the system is neglected by the home owner, and the tank is not cleaned out frequently enough by your local septic tank pumper. As time passes, solids continually accumulate in the tank. As the scum and sludge layers thicken, the clear water middle layer of effluent eventually gets “squeezed out”. As this happens, solids will overflow into the leaching system every time water is run in the house.
The Leaching System
There are several different types of leaching systems. The purpose of the leaching system is to distribute the treated effluent that overflows from the septic tank into the ground. Every time water goes down a household drain, some water (effluent) flows into the leaching system. The most common type of leaching system is a conventional leach field with a distribution box. Other types of leaching systems include raised leach beds, modified raised beds, stone area beds, drywalls, and leach fields on drop boxes rather than a distribution box. When a septic system is designed for an individual home, many factors include separation distances from the home, wells, neighboring wells, water lines and other utilities, property lines, trees, streams, bodies of water, and ground water. “Percolation test” results reveal how well the soil on the particular site accepts water (different types of soil leach at different rates). “Deep hole test” results reveal the soil conditions on the site and the depth to ground water, seasonal ground water, bedrock, or other barriers to drainage in the soil.
Leach fields consist of a series of trenches that usually stem out from a distribution box. These trenches are sometimes filled with stone with a perforated pipe running through the stone. Gravel-less leaching chambers may also be used in place of the pipe and stone leach lines. Different homes and site conditions require varying amounts of leach lines (measured in linear feet). The number of bedrooms in the home and the percolation rate of the soil are used to determine the number of feet of leach line necessary. As the “clear” effluent flows out of the septic tank, it drains into the leach lines and into the soil.
Drywells are most often made of precast concrete. They have closed tops, open bottoms, and holes in the sidewalls. Drywalls can only be installed in particular site conditions. Drywells can only be installed in particular site conditions where the soil is very gravelly or sandy and where there is no issue with bedrock or ground water. Drywalls are installed in a large hole with gravel around the sides and bottom. Similar to a leach field, as the “clear” effluent flows out of the septic tank it drains into the drywall and into the soil.
Why Maintain Your Septic System
There are three reasons why septic system maintenance is important to you and your community. The importance of maintaining your system can be compared to the importance of maintaining your car’s engine. The responsible automobile owner knows that the car’s oil must be changed every few thousand miles. If you do not change your car’s oil change periodically, your car’s engine will eventually fail. The same principle is true for your septic system. While changing your oil is the most important aspect of maintaining your automobile, pumping your septic tank is the most important aspect of maintaining your septic system. Every septic tank must be pumped out at least 2 to 3 years. The size of the tank and the number of people using the system are important factors used to determine how often the septic tank should be pumped. No septic tank should go longer than 3 years between pumping. In situations where a large number of people are using a small septic tank, it is not uncommon to have the tank pumped annually or even more frequently. If the septic tank is neglected, solids will overflow from the tank into the leaching system. This will result in clogged leach lines, contaminated soil, and ultimately leach failure.
The three reasons to be diligent about septic pumping maintenance are:
- MONEY: The cost and effort to get your tank pimped every 2 to 3 years is minimal. By pumping your tank regularly you can avoid costly expenditures of $3000 to $10,000 or more when a leaching system needs to be replaced.
- THE HEALTH OF YOUR FAMILY AND COMMUNITY: Inadequately treated wastewater can pose significant human health risks and can contaminate wells, groundwater, and surface water sources.
- PROPERTY VALUE: A failing or improperly maintained septic system will result in a decline in the value of your property. When the time comes to sell your property, it will be critical that your septic system has been maintained properly and that it is working properly.