Maintenance or surveillance audits are required for ISO 14001 and EMAS. These are undertaken to confirm that the EMS continues to conform to the standard it was certified or registered to. The frequency of surveillance audits is usually every six months, and the emphases are on continual improvement and corrective actions. Another area that the audit will want to visit is the environmental complaint file. There is no easy way to prepare for a surveillance visit, except to ensure that the company continually pays attention to its EMS.