More than two million acre-feet (MAF) of water transfers from agriculture to urban and instream are discussed and debated in California. We use a regional agricultural production and water transfer model to evaluate potential third party impacts of transferring one MAF of water from the Central Valley of California. A range of impacts is estimated under three different scenarios. Our base scenario shows that the adverse economic impacts in the area of origin include a $170 net personal income loss for each acre-foot of water transferred, and 8 job losses for each thousand acre-feet of water transferred.