10 commandments for your septic system.

1. Thou shalt not pour greases, fats and oils down any drain.
2. Thou shalt not attach a garbage disposal to your sink for ridding thyself of meat bones, coffee grounds or other foods that are difficult to biodegrade. 
3. Thou shalt not dispose of paints or household chemicals in the drain (yea, verily, thou shalt use disinfectants in small amounts).
4. Thou shalt not dispose of any automobile fluids down any drain, be it gas, oil, transmission or brake fluid, grease or antifreeze.
5. Thou shalt not kill the beneficial bacteria in your septic system by rinsing pesticides, herbicides or any other toxin down the drain.
6. Thou shalt not dispose of any non-biodegradable items in your toilet, be it cigarette butts, disposable diapers or feminine hygiene products.
7. Thou shalt not let the water run whilst washing dishes and thawing frozen foods, and shall consider limiting flushes. 
8. Thou shalt not run half loads in the dishwasher or washing machine and shall stagger wash loads.
9. Thou shalt not use chemicals to clean up your septic system, lest they harm the septic tank, drainfield and grounwater
10. Thou shalt not attach water sources such as sump pumps to the septic system.

(from Max Haas Septic Services)