Septic tanks: what is it, drainage, how it works, sizes, types

Septic tanks are a notion known to very few people. It is commonly used in rural districts rather than urban areas as they require a relatively large terrain so that all modifications and additions to the household can be attached.

It adds great significance to those that need it and even greater value to those that own it. You will never fail to add to a survey the great opinions and thoughts shared by the owners of septic tanks. They will always tell you how important the usage of this wonderful conception was.

There is a strong possibility that you’ve probably never even heard of one, especially if you’ve lived in a home associated with the primary sewage line.

It adds so much more value to the household associated that it started to become one of the main things individuals seek in a property before investing in it and making a decision.

You never know what the future reserved for you. That’s why I will thoroughly explain the importance of owning a septic tank, along with all the significant benefits added to the estate.

What is a septic system?

man strengthening septic system

A septic system is composed of different components designed to filter and treat a variety of waste thrown away by individuals:

  • Human waste
  • Food scraps
  • Oils and different substances
  • Soaps and other chemicals

It is commonly believed that every individual should contribute to cleaning the used water that needs treatment. That also includes businesses and industrial factories of any type. You must probably wonder why an individual should care about such things.

Every person is responsible for looking after the waste produced and left behind, finding solutions, and taking care of the problem from the root.

To better understand my theory, seize a moment of imagination. Presume what would happen if the local shared sewage system would not process tomorrow, all the sewage and waste generated in the neighborhood. It would be a total disaster as if it’s not already. Some people started to perceive these potential threats and saw a benefit to separating themselves and taking matters into their own hands. Literally.

Every standard septic system is composed of three main components:

  • A septic tank
  • A drain field or a soil osmosis field
  • A well-thought pipe system

How does it work?

installing a septic system

The organic contents and floatable matter are separated in the septic tank, which is the first line of defense. It is later transferred through a series of pipe systems to the drain field or soil absorbent field. The bacteria in the fluids discharged are treated with different pollutant products. The final destination of the waste that left your house is then transferred into the groundwater, the primary water source that returns to your home through another series of pipes.

It may not be easy to understand the whole process. For that reason, I’ve also broken down the process into more straightforward steps so that you may better understand the flow of waste purification.

  • The source of waste that originates from the primary fluid generating components of your household is transferred through a network of pipes.
  • The waste runs through the septic tank.
  • Solidified materials are strained inside, developing into sludge.
  • The oily substances are suspended at the top, developing into scum.
  • The anaerobic bacteria ( bacteria that do not rely on oxygen ) existent in the septic tank sustain themselves on the organic wastewater pollutants.
  • The fluids then pass through a filter near the vent.
  • The resulting filtered fluids stream through a network of pipes that connect to the drain field.
  • The small punctures in the pipes located in the drain field allow the fluids to dribble onto a layer of pebble.
  • Aerobic bacteria (reliant on oxygen) tear down pollutants as fluids filter gradually through the pebble layer into the groundwater.
  • Any leftover contaminators (parasites, viruses, dangerous bacteria) are removed from the groundwater.
  • Once the purified fluids have reached groundwater, they are cycled back to your home through a pipe system.

You might as well already benefit from a septic system without realizing it. Some indicators may suggest the existence of one:

  • There is a well nearby your property that you have access to.
  • The waterline connected to your property does not have a meter 
  • The absence of ”Sewer charges” on any of your bills
  • Neighbors around you already own a septic system 

There are plenty of objectives that drive people to obtain such a septic system. It’s only regular as it requires a strong upfront investment that will provide services to the property for years to come at lower costs than usual sewage service providers. The main benefit is not reducing the cost of bills but enjoying onsite water filtering systems that provide superior quality to the overall service.

concrete sewer

Committing to the ownership of such a system also comes with extra responsibilities for the property owner. Septic systems require regular maintenance interventions. Not taking care of the overall system maintenance will later cause issues that only the owner will responsibly pay for to further benefit from its exceptional services.

Types of septic tank

A septic tank is one of the main components of a septic system.

It’s a sealed box, watertight with connectors such as inlets and outlet pipes. The primary purpose of a septic tank is to filter the waste that flows through it and be kept there for as long as it needs to trigger the development of scum and sludge. It allows the remaining fluids to pass on through the outlet filters to the drain field.

Because of the multiple processes that take place simultaneously in the septic tank, it’s separated into three main layers that complete the whole process.

installation of a concrete sewer

The first layer (Scum)

The oily substances are suspended at the top of the tank forming the first layer called scum.

The second layer (Partially-filtered waste)

The central part mainly contains partially filtered waste.

The third layer (Sludge)

Solidified materials are strained at the bottom of the septic tank, developing a sludge layer.

The first and third layers reside in the tank where anaerobic bacteria.

The anaerobic bacteria continuously break down the first and third layers, feeding on them as much as possible. Any residual left that the bacteria can’t break is further pumped out, so there’s always room left for the next load of waste ready to enter the tank.

The second layer that contains the partially filtered fluids departs from the tank through filters to the drain field ( or the soil osmosis field ), where different filtering processes continue through pebble and soil.

Septic tanks are manufactured in different ways, each varying in toughness and longevity. Depending on the material used in the building process will add various benefits and downsides to the quality of the tank. I’ve categorized and added a summary for each type of material used in the fabrication:

sewage truck


Septic tanks made of concrete will last for generations so that even your grandchildren can benefit from this wonderful system. The tremendous downside to concrete is cracking that may occur if the tank is not maintained correctly.

It shouldn’t be considered an issue if you are a committed individual. As long as proper maintenance is applied to the tank, it will probably be functional when your grandchildren start to emerge.


Ones made of steel are durable up to a point in time. It usually takes around 25 years before they begin to rust. For that specific reason, it’s unlikely that property owners will have it on the number one priority list.

When it starts to rust, the main pillars of the rust will start to weaken along with the ceiling. That poses a great danger to the people that walk above the tank as they could fall along with the ground due to the weakness of the material.

If steel is still the choice you wish to opt for, you should always check for rust development along the main structure of the tank.


Fiberglass ones are less prone to cracks than their concrete and steel counterparts. Fiberglass is a light material that makes an easier attachment of the components. The downfall of the material comes with its flexibility. Ones made of this material are anticipated to shift when the soil around them starts to be soaked.


The material plastic septic tanks are made of is by far the cheapest version of all. They are less prone to cracks than the previous options. Their lightweight composition presents both a benefit and a failure.

When installing a plastic one, you should consider the fragility of the material, as it can break upon installation. It can also levitate to the ground if it’s not assembled correctly.


The most expensive version comes to your aid whenever one of the other options has failed you. This option is usually chosen as a replacement for the previously failed system powered by electricity.

Like all other options, it requires regular maintenance to ensure extended system functionality.

Septic tank sizes

The most frequently asked question regarding the size of a septic tank is: Can it be too large?

The shortest answer to that question is no. A septic tank can only be considered too small, as a lower available space area will have difficulties filtering and separating larger quantities of waste. As long a proper installation was performed, it is secure to use a larger version to aid the flow of more significant amounts of fluids and waste.

Before determining which size fits well according to your requirements, some calculations need to be done to make a better decision.

The most critical factor is considering the number of people your property may accommodate.

Please refer to the table attached below to understand the size best suitable for you.

Number of BedroomsDrainfield SizeMinimum Septic Tank SizeMinimum Liquid Surface Area
2 or less800 – 2500 Sq. Ft.1000 – 1500 Gallons27 Sq. Ft.
31000 – 2880 Sq. Ft.1000 – 2000 Gallons27 Sq. Ft.
41200 – 3200 Sq. Ft.1250 – 2500 Gallons34 Sq. Ft.
51600 – 3400 Sq. Ft.1500 – 3000 Gallons40 Sq. Ft.
62000 – 3800 Sq. Ft.1750 – 3500 Gallons47 Sq. Ft.

How often should it be pumped?

I am sure you would expect an answer that will make you feel demotivated, but the average septic tank should be pumped every three to five years. Because of the anaerobic bacteria that constantly break down the remaining waste, it rarely presents more significant waste deposits that cannot be disintegrated.

The aerobic septic tanks are the only exception to that rule. This type should be inspected and pumped yearly because of its mechanical components. A facility contract is the best approach to save yourself the trouble of inspection.

septic truck

Cesspool vs. septic tank

The difference between the two mechanisms is colossal.

A septic tank’s principal function is to filter the waste that passes through it and hold it there for however long it is necessary to cause the formation of scum and sludge. It allows the residual liquids to travel through the filters to the drain field.

A cesspool is an underground hole filled with cement or stone without any possibility to filter the waste and fluids that pass through it, resulting in soil pollution.


How long does a septic tank last

The longevity of a septic tank varies a lot based on the material used in the fabrication process of your desired unit. Regardless of the option, it should last you for decades if it’s properly maintained.

An average lifespan of a septic tank should fall between 15 to 40 years. Concrete ones make the only exception to this rule. They should last well over 40 years with the proper attention and maintenance.

How much does it cost to replace a septic tank?

A septic tank can only be replaced when it’s in a state beyond reparation. A specialist should have no issues in helping you with this matter. It doesn’t come cheap, as prices vary between $3,000 and $8,000.

How to tell if a septic tank is full

A few apparent factors will generally tell you when the tank reached its capacity:
– A surplus of water accumulated through your drain field
– Visibly slower drainage process throughout your house’s primary water sources
– An unpleasant smell coming from the tank
– Sewer outflow (also the most evident and dangerous)
– Gurgling sounds of water

What to do after the septic tank is pumped.

Any septic tank owner should adequately maintain and facilitate the overall function system of its structure.
There are some things to keep in mind after you’ve got your tank pumped:
– Schedule the next appointment so that you meet the regular basis requirements of pumping.
– Don’t flush unnecessary waste that will make things harder for your septic tank.
– Get to know the components well.
– Always inspect all of the accessible components for possible issues that require immediate intervention.

So we’ve convinced you to install your system. What’s next?

First, you must examine the property to see if it can integrate a septic system. You can start with:

How to find a septic tank

  1. Search through the property’s drawings and legal documents.

  2. Search the property for manholes.

  3. Get in touch with a septic system utility provider to better help you with further indications and services.


There are many benefits to each type that you can own. Having a septic system installed on your property benefits both the community services and yourself. All of the benefits and downsides are named throughout this article. You should be able to find all of the information required so that you make a decision.

What are you waiting for?

concrete septic system