If you use any water in your residence, it must be disposed through an approved septic system. The purpose of the system is to remove most of the harmful items that might get into the water.
Septic systems require periodic maintenance.
Properly maintaining your septic system is the key to its efficiency. Waste water from the house flows into the septic tank. The purpose of the tank is to hold the water long enough so that the solids can settle out. Lighter particles form a scum at the top. This process leaves a middle layer of partially clarified water.