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Classifying Water and Wastewater Systems

The classification of a water or wastewater system determines the required level of operator certification. Systems are classified according to complexity. The following summarize how systems are classified.

Water Systems

All water systems using a surface water source and serving at least 25 individuals per day, or 15 service connections, for more than 60 days per year are required to have a certified operator. Also, all water systems using groundwater and serving at least 25 of the same individuals per day for at least six months per year are required to have a certified operator.

Water systems serving less than 25 individuals per day, AND water systems using a groundwater source serving at least 25 different people per day for at least 60 days (transient non-community systems such as restaurants or hotels)

No certified operators required.

Water systems serving fewer than 500 people and fewer than 100 service connections

Small Untreated:
  • No chemicals added to the water.
  • May have passive forms of treatment, e.g. softening, cartridge filters, etc.
Small Treated:
  • One chemical added to the water.
  • May have passive forms of treatment, e.g. softening, cartridge filters, etc.
Water Treatment:
  • Systems that add more than one chemical, have membranes, do chemically aided filtration, or use UV light to meet an inactivation requirement.
  • Classified according to a point rating system. View the classification worksheet (XLS)

Water systems serving more than 500 people or more than 100 service connections

Water Treatment: and

Water Distribution:
Additional detailed information concerning water system classification (PDF)

Wastewater Systems

Wastewater systems serving fewer than 500 people and fewer than 100 service connections

No certified operators required.

Wastewater systems serving more than 500 people or more than 100 service connections

Wastewater Treatment and

Wastewater Collection
For additional detailed information concerning wastewater system classification (PDF)