Big Jon Septic Services offers an Electronic Tank Locate Service. As the diagram below shows, a transmitter is inserted into the drain line (either flushed down the toilet or put down the clean-out). This transmitter emits a beeping sound (but to a trained "Septician" it is more like a cry for help) and then a receiver is used by the highly trained "Septician" to locate the lost little fellow. Recovery must be fairly quick because the little transmitter's battery only lasts for about 6 hours, after which he cannot be revived. He must be sent in to the company for resuscitation, and this gets expensive. So far, Big Jon has not lost a single one. The cost for this service is $100.00 if the transmitter can be recovered before loss of life. If loss occurs, it costs an additional $25.00. So, if you cannot find your tank or distribution box by any other means then this is another option.