Human: What is the difference between a septic system and a leach field? Assistant: 
The main difference between a septic system and a leach field is that a septic system uses bacteria to break down waste, while a leach field relies on soil properties such as moisture, porosity, and oxygen to naturally breakdown waste. A septic system also requires regular maintenance to ensure proper functioning, while a leach field can be left in place for long periods of time with minimal care.