For most households, the waste that runs from the sewer system is directed to a treatment plant. There is, however, instances where a connection to that main line cannot be established and in such cases a septic tank are used instead. Septic tanks are stand alone units that handle waste from one single household in most cases unlike the multiple users that main sewer treatment plants offer. A qualified septic tank contractor will help you with your installation and even with your septic tank maintenance.