| Plant Type | Required Minimum Operator Grade |
Required Minimum Assistant Operator Grade |
| Water treatment plant with facilities for filtration* which treats 2.5 MGD# or less | IIA |
IIA |
| Water treatment plant without facilities for filtration* which treats 2.5 MGD# or less and serves more than 1,000 people | IIB |
C |
| Water treatment plant that serves 1,000 people or less | C |
None Required |
| Distribution system serving 1,000 people or more | D |
None Required |
Note: * filtration means a treatment process which includes slow sand filtration, gravity rapid sand, anthracite coal filtration, pressure filtration, diatomaceous earth filtration, or other processes determined to acceptable treatment under Subpart 5-1.
# MGD = million gallons per day.