septic leachout systems can usally be spotted by looking in the yard where the grass is greenest. in my area they are made with a catch basin and clay tile layed out in a rectangular pattern below the frost line. carefully digging down should expose the pipe. does your city require that plans be filed when the system was put in? if its working okay i wouldnt worry too much. do you have the option to hook up to the city sanitary? some areas have catchbasin cleanout contractors