There is a need to measure deep in situ moisture conditions for all types of waste storage facilities in a safe, cost effective, practical, and efficient manner. This paper describes the Deep Diviner moisture probe, a deep capacitance moisture sensor, which has been developed by the authors with the assistance of the Canada Industrial Research Assistance Program (IRAP). The deep capacitance moisture probe uses the Diviner 2000, a portable capacitance soil moisture monitoring sensor manufactured by Sentek Sensor Technologies. This portable probe was developed for irrigation management, and is a nonradioactive sensor. Development of the deep capacitance moisture probe involved modifying the Diviner 2000, which has a limited depth range of 1.6 m, to allow the measurement of volumetric water content to depths of 40 m or 50 m, and possibly deeper. A winch / cable assembly was developed to lower the sensor down within a PVC access tube to allow for fully automated measurement of in situ moisture contents at user specified depth intervals, each of which are recorded on a portable datalogger. The prototype of the deep capacitance moisture probe was tested both in the laboratory and in a full-scale field situation to ensure the required hardware modifications were functional. Full scale field testing was also completed on the prototype. The results of this testing show that the deep capacitance moisture sensor is capable of measuring the water content of till and sand materials to depths of 6 m. This paper describes the development and testing of the deep capacitance moisture.