Increased water security and economic efficiency are necessary, but not sufficient, conditions for improved welfare. Another key dimension is the “social” dimension, including equity. Most people in society will feel their own welfare depends not only on their own individual exposure to water risks but also on the distribution of risks among citizens. When considering which particular instruments should be used to meet a given target for water risk, an assessment should be made of how much each instrument (or each “instrument mix”) is likely to contribute to the goals of water security and economic efficiency (in part, following OECD, 2008).