Your septic system should be restructured. It is important to become familiar the septic system. Are there guidelines and the best way to follow them? You should only flush out toilet paper and human waste. There are a variety of septic systems; ecological septic tank, conventional methods, evapotranspiration systems filters made of sand, and much more. A household septic tank must be flushed every three or five years. gykhsudkl6.