<human>: What are the most common questions that people have about septic tanks?
<bot>: 
1. What is a septic tank and how does it work?
2. Why do I need a septic tank in my yard?
3. How often should I empty my septic tank?
4. Are there any health risks associated with having a septic tank?
5. Can you help me find a good local plumber to service my septic tank?