The Three Different Types of Septic Systems

Posted on: September 20th, 2017 by megan No Comments

All septic systems aren’t created equally. While the basics of every system tend to be pretty similar, there are different types of systems out there that can affect the way wastewater is processed and effluent is distributed. So, what are the major types of septic systems? Let’s take a look. 

1. Standard septic tank systems:

Standard septic tank systems, also known as gravity flow systems, are the simplest type of septic system available. They rely on gravity to separate out materials from wastewater based on their density. In a standard septic tank system, wastewater exits your home and then enters into the first compartment of the septic tank. Heavier waste falls to the bottom, forming a thick sludge, while grease and lighter materials rise to the top and form a scum layer. The fluid between, known as the effluent, then flows into a second compartment and moves through a distribution box situated right at the beginning of the leach field and is then distributed throughout the soil via a piping system.

2. Low pressure dose system:

A low pressure dose system typically tends to be more complicated than a standard septic system. Like in a standard septic tank system, once wastewater exits the home, heavier materials in the water fall to the bottom and form a sludge while lighter materials rise to the top and form scum. The effluent similarly flows into a second compartment but it isn’t distributed out directly into the soil. Instead, it enters into a pump tank where it is stored, and it is then pumped into the leach field. Only from there is it distributed into the soil via a network of many small diameter pipes operating under very low pressure (this is why this type of system is known as a low pressure dose system). The effect is that the effluent is distributed much more slowly and evenly throughout the soil, making it easier to absorb.

3. An engineered or supplemental treatment system:

An engineered septic tank treatment system, sometimes also called a supplement treatment system, is by far the most complex type of septic system. It essentially functions the same way as a low pressure dose system functions. However, there is one major difference: the effluent is pre-treated after leaving the pump tank before it is distributed. Because these types of systems are more complex, they require more maintenance, and an annual check-up is recommended.

So, how can you decide which type of septic system is most appropriate for your home? Well, ultimately it boils down to the quality of your soil, groundwater levels and overall percolation rates (how quickly water flows through the soil). If the soil quality is poor, groundwater levels are high or percolation rates are very high, and absorption will be slower. This means that you will likely need a low pressure dose system or an engineered treatment system to ensure effluent isn’t being put into the soil at a faster rate than it can be absorbed, which can generate problems. When it doubt, your best bet is to consult with a professional to figure out what type of septic system is most appropriate for your home.