Conventional Septic System - What is a Conventional Septic System?

This is the most common type of septic system that people are familiar with (hence, Conventional). Conventional Septic Systems are identified by names like: Conventional, Overflow, and Leach Field System.

Here is a typical Septic System Layout:

These names all refer to the same type of system. Don't get confused by the different names. The term Overflow is actually the most accurate way to describe the operation of your septic system. Wastewater from your plumbing (sinks, showers, commodes, etc.) flows by gravity to the inlet of your septic tank. This is the beginning of the process of treatment and disposal.

The inlet of the tank should be equipped with either a baffle, or a pipe fitting that diverts the wastewater downward as it enters the tank. The reason that the wastewater is diverted downward is to attempt to increase the amount of time that the wastewater "spends" in the septic tank. This time is referred to as "Detention Time". Over time, materials in the wastewater stream that are heavier, and lighter, than water will separate (sink and float) within the septic tank.

It is very common for a homeowner to notice that their drains are running slow, and look inside their tank to see that the inlet baffle is clogged. Many will simply remove the baffle. Without this baffle, wastewater now has the potential to "short-circuit" the detention time by flowing over the top of the "floatable" layer in the septic tank. This will likely begin the ultimate failure of the septic system.

Here is a typical Septic System Break-Out: Neighbors will love you if this is in your backyard!! This WILL smell!

So, if the baffle is working properly, wastewater will flow through the septic tank, and eventually "Overflow" the outlet of the tank. The septic system must now have a place to make the overflow go away. This is where the trenches in the yard come into play.

The trenches receive the overflow from the septic tank by gravity. Once the septic tank is full (usually within 5 to 10 days after moving into the home), the system becomes an "on-demand" system. Meaning, what-goes-in, must-go-out. There is NO storage in the septic tank. So, the treated wastewater begins to fill the disposal trenches.

As the water enters the trenches, it begins to percolate (hence, the term "perc test") into the soil below the trenches. The trenches are all connected together with the same "overflow" technology as the rest of the septic system (gravity is very cheap!). If you have multiple trenches, the first trench will likely be the only trench receiving wastewater. This trench will eventually become saturated (stay wet all the time), and because of lack of oxygen, will form a "Biomat" in the bottom of the trench. This Biomat will act like a liner in the bottom of the trench, and will prevent the wastewater from percolating into the soil below. Now, the wastewater "overflows" to the next trench.

Here is another view of the same Septic System Break-Out:

Eventually, all the trenches will form a Biomat, and the wastewater will have to find a new place to go. There is usually no place left to go, but up. Wastewater will now begin to "break-out" onto the surface of the property. Surfacing of wastewater is always a sign of a problem.

As the owner, you will now be required to install the back-up disposal system. If there is no area reserved for a back-up system, then a connection to public sewer may be required. If there is no public sewer available, then you will have to find a very expensive solution, or vacate the home.

Please Contact Me before this happens to you.