Extraction, transformation and Loading (ETL) is the process of storing data into the data warehouse. Errors in the ETL process con result in wrong data being stored. This paper introduces an automated approach to reconcile the source data with data stored in the data warehouse. This ensures that data in the warehouse is consistent with the source data and all stakeholders have clarity on the quality of the data. The ETL Unit presented in the paper can be considered as a template/ design pattern to implement this strategy. The pattern will help to for implementing both integrated and independent Auto Reconciliation.