The Permit Compliance System (PCS) is an EPA national computerized management information system that records water-discharge permit data on more than 64,000 wastewater treatment facilities nationwide. This system automates entry, updating, and retrieval of National Pollutant Discharge Elimination System (NPDES) data and tracks the issuance of permits, permit limits, monitoring data, and other data for facilities regulated under NPDES. The Compliance Schedule Violation File contains data from the most recent 2-year period, regarding a set of compliance schedule events. These schedule events include milestones a permitted facility must accomplish to upgrade the quality of its effluent discharge when such milestones have been established as a condition for granting a permit or when complying with an enforcement action. This data is updated twice a year.