If you live outside the city sewer system, you need a septic system to remove waste water and sewage from your home. Sewage systems contain contaminated water and can cause sickness is not installed and working correctly. For this reason you need to understand how the system works. You should also check with your local codes to make sure you are placing the system far enough from your ground water as well as making sure it is big enough so it does not over fill and seep on to the top of the soil. This video shares these requirements in detail.