In many cities the definitions of septic tanks, lined tanks and various types of pit are used interchangeably. It is therefore important that those providing the data for the city understand the types of sanitation system in use and how they function. When producing an SFD it is recommended that where possible discussions are held with stakeholders to ensure that the functionality of each system is understood. You can use the Sanitation System Classification Tool to help select from the SFD selection grid the correct sanitation systems in use in your city. If you require any assistance in classifying the system you are considering the SFD Helpdesk would be happy to help you.