A study has been conducted to compare the quality of the lechate from spent shales that have been premoistened to approximately fifteen percent water concentration with deionized water and with co-produced retort water. The premoistened shales were compacted, aged for periods up to one month, leached according to the RCRA procedure and the ASTM standard leach test, and the leachates analyzed for various parameters including 40 metals, ammonia, TOC, and numerous others. The data gathered from this study con be used to assess the potential environmental impact that may result from co-disposing of shale and process water. The economic advantages of co-disposal are obvious: it lessens the requirement for plant make up water to wet the spent shale prior to disposal and it eliminates the need to treat the process water prior to reuse or disposal.