The person or team responsible for the technical management, storage, and maintenance of a dataset on behalf of the data owner.
The data custodian implements the policies set by the data owner. While the data owner decides what data is collected and how it should be used, the custodian ensures the data is stored securely, backed up, accessible to authorized users, and technically maintained. In many organizations, the IT department acts as custodian for data owned by business units.
The distinction between owner and custodian is important for accountability. The owner is responsible for the data's content and use; the custodian is responsible for its technical integrity and availability.
Example: A city's planning department owns the zoning dataset — they define what it contains and who can use it. The GIS team acts as custodian — they maintain the database, apply updates, ensure backups are current, and manage access permissions. If the data is incorrect, the planning department is accountable; if the database goes down, the GIS team is accountable.