What are the documents need to be check before buying a flat?

The following documents should be checked before purchasing a flat: 1. Title Deed or Mother Deed or Parent document of the property.. 2. Property Tax paid receipts for at-least previous 15 years for the land on which the apartment is built to ensure that property taxes have been paid till date. 3. Government approved Building Plan for building the apartment. If the apartment is already constructed check if they have built as per the plan . 5. Commencement Certificate given by the Municipal Corporation if the construction has not begun yet or if the building is in the initial stages of construction. This contains all the permissions given to the builder for construction. etc