As with most questions about septic tanks and systems, the answer as to how often it needs to be pumped is based on the size of the tank, the number of people in the household, and the amount of wastewater produced and draining into the septic system. As a general guideline, most residential septic tanks should be pumped out every three to five years. However, if the house has multiple people or if the septic system is older and has a smaller septic tank, it is recommended to consider pumping the tank every two to three years. Proper tank and septic system maintenance is also important to prevent backups in the system if the tank is not able to break down the solid waste materials. Households can also help prevent problems with the septic tank by reducing the volume of solids in wastewater and reducing the amount of grease, oil, or chemicals and cleaners disposed of through the wastewater.