The paper presents a novel agile approach to large scale design of enterprise data warehouses based on a Data Vault model. An original, simple and direct algorithm is defined for the incremental design of physical Data Vault type enterprise data warehouses, using source data meta-model and rules, and used in developing a prototype case tool for Data Vault design. This approach solves primary requirements for a system of record, that is, preservation of all source information, and fully addresses flexibility and scalability expectations. Our approach benefits from Data Vault dependencies minimizations and rapid loads opportunities enabling greatly simplified ETL transformations in a way not possible with traditional (i.e. non data vault based) data warehouse designs. The approach is illustrated using a realistic example from the healthcare domain.