A stand-alone systems analysis approach has been taken to the performance assessment of a small wind powered reverse osmosis plant. The study is concerned with the sensitivity of operation to key parameters: wind speed, battery storage capacity and reverse osmosis operating pressure. it is demonstrated that the results of such a system analysis can be inconsistent with more simplistic approaches sometimes adopted in this applications area. A provisional calculation of annual expected water delivery has also been undertaken. Detailed modelling results are presented and discussed. Given that only discrete sizes of reverse osmosis equipment are ih practice available, it is concluded that the ideal operational pressure is not always the maximum design pressure, but can depend on the site wind speed. Since water storage is far cheaper than electricity storage, there is motivation to minimise the capacity of the battery store. The most effective battery capacity would seem to be in the range of 4 to 8 h at nominal rated load for the reverse osmosis plant, with the actual value critically dependent on wind speed at the site.