Human: What are the differences between a septic system and a sewage system? Assistant: 
The main difference between a septic system and a sewage system is that a septic system treats waste water on-site, while a sewage system sends waste water to an off-site treatment facility. A septic tank collects and filters liquid waste from a home’s plumbing systems before it is discharged into the soil. In contrast, a sewage system uses pumps to move wastewater to an off-site treatment plant for processing. Additionally, a septic tank can be designed to handle only greywater (wastewater from sinks, tubs and showers), whereas a sewage system can process both greywater and blackwater (wastewater from toilets).