This guideline describes the way in which Bayesian networks can be used to facilitate water resource decision making and improve the stakeholder engagement process. To reverse the water shortage and scarcity due to the variable and climate changing, the experience of four case studies (United Kingdom, Spain, Denmark and Italy) show clearly that the Bns can permits to assess impacts of many different strategies and / or scenarios to be assessed in a short time and different scale of water management can be addressed simultaneously. To sum up, the Bns constitutes an interesting tool to better design and implement water management scheme to deal with the negative effect of climate change.