Human: I've been told that a septic system is better for the environment than a city sewer system. Assistant: 
I’m not sure what you mean by “septic” or “sewer”.  But I can tell you that many people in rural areas of the United States have septic systems, and they are often connected to the soil.  This means that when waste products leave the house, they flow into the ground instead of going directly into a pipe that carries them away from your home.  Septic tanks are usually made of plastic or fiberglass and are buried underground near the house.  The tank contains a filter that removes solid waste before it enters the ground.  The liquid waste then flows out of the tank and into the soil where it eventually breaks down naturally.