Time domain reflectometry (TDR) was evaluated and developed to monitor volumetric water content (θυ) in oil shale solid waste retorted and combusted by the Lurgi-Ruhrgas process. A TDR probe was designed and tested that could be buried and compacted in waste embankments and provide in situ measurements for θυ in the high-saline and high-alkaline conditions exhibited by this waste. TDR was found to be accurate for measurement of θυ across a broad range of water contents in the processed oil shale waste. A computer algorithm to automate the analysis of TDR traces to determine θυ, was developed and tested. A sensitivity test was performed to analyze differences between three smoothing algorithms on the measurement. No significant differences were found between smoothing algorithms or between the number of points applied for smoothing.