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Septic System Anatomy Video


Am I glad you are here today! Guess what I discovered? I found a septic system that is being installed and it hasn’t been covered over with dirt. The inspector is coming tomorrow, so it is a great opportunity for me to show you the basic components of a septic system. The septic system consists of the septic tank, the distribution box and the leach field.

This is the actual septic tank. It is a precast, concrete structure that a crank lowers into place. This particular one is about 750 to 1,000 gallon capacity. The waste water from the house comes directly into this tank. The tank has lids that allow you to inspect the inside of the tank. They also serve a very important service. Every three to four years, you need to have a company come in and pump out all of the solids, that have collected inside the septic tank.

The distribution box takes the waste water from the septic tank and directs it out to the leach field through four different pipes.

The leach field in this system looks a little weird because of all the concrete covering. This leach field will actually be underneath the road leading to the house. The waste water enters the leach field from the distribution box. The leach field consists of a foot thick layer of sand. The waste water filters down through the sand, where it gets cleansed of all the bacteria and pathogens. And then it flows back into the water table.

That is how simple septic systems work.

Author's Note: We've received other questions with similar problems or questions. Here's one from Howard Stein of Oklahoma City, OK, regarding his home septic system.

"We have ten inches of snow and the temperature is near zero Fahrenheit. It will stay like this for several days.  Is it safe to use our washing machine (doing regular laundry) in this frigid weather since we have a septic tank and fear that the "arms" cannot properly dispose of large volumes of water into the ground?  Many thanks for your help."

Howard, typically in most septic systems, the tank and drainage fields are located well below the frost line.

Tim Carter


5 Responses to Septic System Anatomy Video

  1. Great video and I did not know anything about a septic tank.....I have city sewer....sent this video to my sister in KY they have a septic tank and as soon as my sister in Illinois gets her computer, I will forward this over to her, they have a septic tank also.....and I really doubt she knows anything about it either 🙂 You are a smart man Tim....and thanks for all the info you give us.....

  2. Inspecting the inside of the septic tank consists of looking at the outlet elbow. Before plastic pipe they used concrete. When they break off the proper drainage is defeated. The design is intended to drain water (only ) from mid tank. With the elbow gone, the tank drains off the top and allows the scum layer to go into the leach field & clog it up. What you show is a little different than what they used in Georgia. There is no distribution box. The leach field is directly downstream from the septic tank. Depending on perk test results, the length of leach field is determined. Hardpan clay can be a devil of an adversary. Here we use big plastic mesh dome looking things & back fill with gravel. there are usually a couple of branches in the drain field.

  3. Hi Tim,

    I enjoy your weekly newsletter, but today I responding to your response to Howard Stein and his septic system with respect to frost concerns.

    I own an architectural design firm and occasionally we are asked to design septic systems in addition to the house project. We are located in Queensbury New York and have a frost depth of 48". The following data comes directly from our Board of Health. 1-The septic tank cover shall always remain accessible and where the manhole is more than 12" below final grade a collar must be used. 2-Typical subsurface treatment systems (leach fields) depths shall be as shallow as possible, but not less than 18" and placed on at least 6" of aggregate... The earth cover over the aggregate should not exceed 12" in order to enhance the natural aeration and nitrogen uptake by plant life. Heavy equipment must be kept away from the field as not to alter the soils characteristics due to soil compaction and to alleviate cave-ins.

    To have a system installed below the frost line is simply not allowed in our neck of the woods. I can't say that it has never happened, but in my 22 year professional career, I've never seen a septic system that was installed under the frost line. The warm temperatures of the waste water in the typical winter used home is enough to inhibit frost development. Once snow falls, it then insulates the warm ground temperatures from the freezing air temperatures.

    Just wanted to pass along my 2 cents.

    Thanks Tim,
    Dan Williams
    Vice President
    Williams & Williams Designers

  4. Good luck on your ham radio set-up. I was an radio-operator in the Army
    Air Force [B-29s ]so it takes awhile to get that code down pat.1943 -'46 .
    I was up to 30 WPM then, I now have amateur KG8XC +extra-class. I wish you the best Tim . I still recall my first CW contact !!

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