Utility Operator 3. UO 3 – Progression from UO 2 to UO 3 in addition to a minimum of 4 years, full time equivalent, CRD experience would also require an EOCP Water Distribution 2 or Wastewater Collection 2 or Wastewater Treatment 2 or Water Treatment 2 Certification. Only employees with three years, full time equivalent, CRD UO 3 experience and EOCP Level 2 Certification (Water Distribution 2 or Wastewater Collection 2 or Wastewater Treatment 2 or Water Treatment 2) will progress to UO 4 Classification.