Improving water use efficiency is increasingly important as California agriculture confronts water shortages. Changing tillage and crop residue practices could help. In regions of the world where no-tillage systems are common -– such as Brazil, Argentina, Paraguay, Canada, Western Australia, the Dakotas, and Nebraska -– generating and preserving residues are an indispensable part of management and sustainable production. Residues reduce erosion, provide carbon and nitrogen to soil organisms, and reduce soil water evaporation, along with other advantages and drawbacks. The water conservation value of crop residues and conservation tillage has not been evaluated in the warm, Mediterranean climate of California. This study measured the effects of residues and no-tillage on soil water evaporation in California conditions.