Why You Should Clean Your Septic Tank

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.

The importance of maintaining your system can be compared to the importance of maintaining your car’s engine. 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 every 2 to 5 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 5 years between pumping’s. 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 and into the leaching system. This will result in clogged leach lines, contaminated soil and ultimately leach field failure.

Three reasons to be diligent about septic pumping maintenance:

1. MONEY: The cost and effort to get your tank pumped every 2 to 5 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.
2. 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.
3. 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.

Understanding Your Septic 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, waste water 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. 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 SEPTIC TANK is a large box that is most commonly made out of precast concrete. Some septic tanks are made of metal, plastic or fiberglass. The size of a residential septic tank depends upon the age of the house, number of bedrooms in the home and the regulations in the county in which it is installed. Typically, a newer three to five bedroom home will have a 1500 to 2050 gallon septic tank. Smaller homes and older homes may have a 1000 gallon septic, or even a smaller tank. While older tanks consist of a single compartment, newer tanks often have 2 compartments. Some homes have more than one tank. When household wastes enter the tank several things occur:

1. 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.2. Three layers form in the middle section of the tank. Organic solids form a crusty layer of “scum” at the surface of the tank. 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 distributes 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. There are several different types of 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, above ground mounds and leach fields on drop boxes rather than a distribution box. When a septic system is designed for an individual home, many factors need to be taken into consideration. Some of these 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). “Profile hole test” results reveal the soil conditions of 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.

MOUND SYSTEM is an alternative to the traditional leach field. The mound is an engineered drain field in areas where septic systems are more prone to failure due to having extremely permeable or impermeable soils, soil with shallow cover over porous bedrock, and soils that have a high seasonal water table. The mound system includes a septic tank, a dosing chamber and a mound. Waste from homes is sent to the septic tank where the solid fraction settles to the bottom of the tank. The effluent is sent to a second tank called a dosing chamber. In the dosing chamber, the effluent is evenly distributed in doses into the mound. Wastewater is partially treated as it moves through the mound sand. Final treatment and disposal occurs in the soil underneath the mound. The mound system can also better handle the effluent because it doesn’t all come into the mound at once allowing the effluent to be better cleaned and helping to keep the mound system from failing.

EVAPOTRANSPIRATION (ET) BEDS are wastewater treatment and disposal that offers an alternative to conventional soil absorption systems for sites where protection of the surface water and groundwater is essential. An ET system is unique in its ability to dispose of wastewater into the atmosphere through evaporation from the soil surface and/or transpiration by plants, without necessarily discharging it to the surface water or groundwater reservoir. However, in certain cases, the ET concept also offers flexibility by combining seepage with evaporation as an alternative option.