Most water utilities operate in an environment of uncertainty, including meteorological, technical, physical, and political risk factors that affect their ability to meet water supply planning objectives. Identifying these risk factors and characterizing their water supply consequences are an important step in development of a long-term water supply plan. CDM has developed an approach to incorporating risk into the formulation of a water supply strategy. Risk issues fall into two categories: risks along a continuum, such as hydrology/weather or water quality; and, risks of discrete events, such as technological failures or regulatory restrictions. The Santa Clara Valley Water District's key internal and external stakeholders were asked what risks and uncertainties concern them that could affect the District's water outlook. In order to keep the evaluation manageable, the most significant, representative, and quantifiable risks were carried through the risk analysis. For example, earthquakes along one of several faults, terrorist activities, and other catastrophic events could all result in infrastructure failure. Of these risk factors, an earthquake in the Delta was identified as having the most significant water supply impacts, as it could interfere with both of the District's imported water supply systems. District staff and outside experts were interviewed to estimate the probabilities and consequences of each risk factor. The results were presented to the stakeholders for their comments. Once the key risks were identified, the technical team developed different scenarios, each corresponding to a different combination of risk factors, and identifying what actions would be required to meet each possible future should it arise. The risk analysis model was used to evaluate both the current baseline and alternative water supply portfolios. Includes figures.