Septic Tank Design Calculations | Building Construction and Design

How to design a Septic Tank?

A Septic Tank is a small scale sewage treatment system used in areas which have no connection to the main sewage pipes that are provided by the Local governments or private Corporations.

In this article, we will detail out all the calculations that are to be performed to get the required volume of a Septic Tank with the help of examples.

Schematic Diagram of a Septic Tank
Schematic Diagram of a Septic Tank

We would begin with a small scale example so that your concept of Septic tank design is clear.

Here are the thumb rules to be kept in mind which will help you in calculating the volume of a Septic Tank.

For a three bedroom house:

The quantity of sewage considered for a three bedroom house should not be less than 900 gallons.

For a two bedroom House:

The quantity of sewage to be considered for the design of Septic Tank should not be less than 700 gallons.

For one bedroom unit:

The quantity of sewage to be considered for the design of a Septic Tank should not be less than 550 gallons.

Let’s begin with an example of a three bedroom residence.

Read more