<human>: I've been hearing a lot about septic tanks and septic systems. What are they and how do they work?
<bot>: Septic tanks are designed to hold wastewater from homes and businesses, which includes human waste and toilet water. The tank is made of plastic or fiberglass and has a lid that can be opened for maintenance and inspection. When the tank fills up, it will need to be emptied by a professional. The wastewater then flows into a drain field where bacteria break down the organic material in the wastewater. This process helps purify the water and prevents contamination of groundwater.