To use LCA for water footprint, you need to follow four main steps: goal and scope definition, inventory analysis, impact assessment, and interpretation. In each step, you should consider specific aspects related to water footprint. For example, during goal and scope definition you must define the functional unit, system boundaries, allocation methods, and data sources. Additionally, you must choose the appropriate water footprint indicators and methods for your impact assessment such as water scarcity, water stress, water deprivation or water damage. During inventory analysis, you must collect and calculate the data on the blue, green, and grey water use and pollution of your product or system in each life cycle stage. You can use databases such as Ecoinvent or WFN or tools such as AWARE to assist with this process. For impact assessment you should apply the water footprint indicators and methods to your inventory data to quantify the potential environmental impacts of your product or system on water resources. You can use software or tools such as SimaPro, OpenLCA or WULCA to support this assessment. Finally, during interpretation you must analyze and report your results highlighting the main findings, limitations, uncertainties and recommendations for your water footprint assessment. Additionally, sensitivity analysis, scenario analysis or trade-off analysis can help explore the effects of different assumptions, parameters or alternatives on your results.