A tank is generally called for in a couple of different scenarios. The first and most common is in more rural areas that do not have public city sewer systems available to tap into. The tax dollars that we pay as residents of a city go partially toward providing sanitary services, one of which is maintaining a public sewage treatment plant and sewer system. If, however, your home or business is located too far away from existing city sewer lines, it becomes necessary to dispose of your own waste by installing a septic tank system. Generally, permanent tanks are relatively affordable, can be installed in a few days, and are reliable.