An individual who makes decisions addressing the operational activities identified in Subsection 63770(b) must possess a distribution operator certificate. The D1 (Distribution 1) certificate exam can be completed as long as you have obtained a high school diploma or GED.

Subsection 63770(b):

  • Water systems shall utilize only certified distribution operators to make decisions addressing the following operational activities:
  • (1) Install, tap, re-line, disinfect, test and connect water mains and appurtenances.
  • (2) Shutdown, repair, disinfect and test broken water mains.
  • (3) Oversee the flushing, cleaning, and pigging of existing water mains.
  • (4) Pull, reset, rehabilitate, disinfect and test domestic water wells.
  • (5) Stand-by emergency response duties for after hours distribution system operational emergencies.
  • (6) Drain, clean, disinfect, and maintain distribution reservoirs.

Minimum Requirements for D1 Examination
High School Diploma or GED

Requirements for Certification
Successful completion of the Grade D1 operator examination within the three years prior to submitting the application for certification.

Expected Range of Knowledge

Exam Schedule
Distribution exams are offered twice a year in March and September. The final filing date for the March exam is January 2 and the final filing date for the September exam is July 1.

Exam Application

More information can be found at the California State Water Resources Control Board site at