If you wonder how often your septic tank needs to be cleaned or pumped out, the answer depends on several factors, including tank size, family size, the design and age of the tank, whether or not your family uses a garbage disposal, etc. In most cases, a 1,500-gallon septic tank installed for use by a family of four will require pumping approximately every four years. However, in some cases, a tank may require pumping more or less frequently. During periods when you host extra guests, deposit large amounts of grease, or in cases of extended periods of neglect (such as when you purchase a new home where the tank hasn’t been pumped when necessary), more frequent pumping may be required. To learn more about how to maintain your septic system, we recommend that all septic system owners review the guidelines published by the National Environmental Services Center.