The study includes analysis of two issues in augmenting water supply: efficiency and equity. The efficiency analysis rests on an operational (computerized) benefit cost model developed to evaluate the optimal timing of investment for water supply augmentation. Benefits in this model are estimated by both an opportunity cost approach and a willingness to pay approach with both parallel shifts and rotating (around the initial intercept) shifts of the water demand curve which is estimated in a linear fashion. The equity portion of the study entails analysis of the geographical distribution of benefits relative to payments with alternative plans for financing the study project. Plans analyzed include: (a) full reliance on a uniform countywide property tax to cover the financial obligation incurred; and (b) a unit charge (long run financial or resource cost) to water districts for delivered water and a countywide property tax to meet any remaining obligation.