1.3 Facility Classifications & Operator-in-Charge Duties

1.3 Facility Classifications & Operator-in-Charge Duties

The class of license you need is not a matter of preference — it is dictated by the Group that SC DES assigns to the facility where you work. Get one thing straight before you read the tables: South Carolina classifies drinking-water treatment plants by the treatment technology and source water involved, not by million gallons per day. Many generic operator study guides present a flow-based table; that is not the South Carolina scheme, and the numbers will not match your exam.

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1. Drinking Water Treatment Plant Groups (Section 40-23-300(A))

The traps in this table

• Groups III and IV both require Class C. The ladder is not one class per group. Memorize the sequence E, D, C, C, B, A.
• Source water is the great divider. The same unit process lands in a different group depending on whether the source is groundwater (Group III) or surface water/GWUDI (Groups IV–VI).
• The 4 gpm/ft² filtration rate and the 2-hour clarification detention time are the hinge values between Group IV (Class C) and Group V (Class B).
• Membrane technology appears twice. On groundwater not under surface water influence it is Group III (Class C); on surface water or GWUDI it is Group VI (Class A).
• Unfiltered surface water is Group IV, not a higher group — a point that surprises most candidates.

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2. Distribution System Groups (Section 40-23-310(A))

Distribution is classified on a completely different basis: reliable production capacity, meaning the total capacity of the system including all wells, surface water sources, and purchased sources, as determined by SC DES during routine sanitary surveys.

Note the fire-protection clause in Group III: a small system that supplies fire flow is bumped up a class even though its capacity would otherwise place it in Group II. Note also that Group I distribution systems require no licensed operator at all — the only "no license" entry anywhere in the South Carolina scheme.

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3. Wastewater Plant Groups

Wastewater plants carry their own group schemes, set out directly in Chapter 51. The letter suffix tells you which ladder you are on.

Both wastewater ladders are clean one-to-one mappings — four groups, four classes — which is exactly why candidates who memorize the wastewater pattern then misapply it to drinking water get the Group III/IV question wrong.

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4. The Operator-in-Charge Rule

Chapter 51 states the requirement the same way for every discipline: the operator-in-charge must hold licensure at a level no lower than the level of license designated for the classification or grouping assigned the plant. Two consequences follow:

• Equal or higher, never lower. A Class C operator may serve as OIC of a Group III drinking-water plant (which requires Class C) or of a Group I or II plant, but not of a Group V plant.
• Discipline-specific. A Class A water treatment license does nothing for you at a biological wastewater plant. The OIC of a biological wastewater plant must hold a biological wastewater license at the required level.

Direct responsible charge — what the OIC actually owns

1. Process control decisions. Chemical feed rates for chlorine, coagulants, lime, and fluoride; filter backwash initiation; sludge withdrawal; aeration tank dissolved oxygen setpoints; and solids wasting rates.
2. Operational recordkeeping. Daily logs of flow, disinfectant residual, turbidity, pH, jar tests, maintenance actions, and chemical inventory.
3. Regulatory sampling and monitoring. Ensuring total coliform, E. coli, disinfection byproduct, lead and copper, and NPDES effluent samples are collected on the approved schedule and analyzed by approved methods.
4. Compliance reporting. Signing and submitting monthly operating reports and Discharge Monitoring Reports, and initiating public notification when required.

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5. Records Retention

South Carolina adopts the federal drinking-water recordkeeping requirements of 40 CFR 141.33 through its state primary drinking water regulations. Learn these by category, because exam questions ask for one specific row:

The pattern to remember: micro is 5, chemistry is 10, surveys are 10, corrective actions are 3, and lead/copper is 12.

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6. Emergency Notification

Two distinct triggers matter, and they come from different regulatory programs.

Drinking-water side: the 20 psi rule

A public water system must maintain a minimum positive pressure of 20 psi throughout the distribution system. Loss of pressure below 20 psi means back-siphonage and pathogen intrusion become real risks, and it is the standard trigger for issuing a boil water advisory and notifying SC DES. Confirmed E. coli in a distribution or finished-water sample, and failure of primary disinfection, are equally reportable.

NPDES side: the 24-hour / 5-day rule

Under the federal NPDES regulations at 40 CFR 122.41(l)(6), which SC DES administers under delegation, the permittee must report any noncompliance that may endanger health or the environment:

$\text{Incident} \longrightarrow \textbf{Oral report within 24 hours} \longrightarrow \textbf{Written submission within 5 days}$

• Oral report within 24 hours of the time the permittee becomes aware of the circumstances. Any unanticipated bypass exceeding effluent limits, any upset exceeding effluent limits, and any violation of a maximum daily discharge limit designated for 24-hour reporting fall in this bucket.
• Written submission within 5 days, describing the noncompliance, its cause, the period of noncompliance including exact dates and times, whether it has been corrected, and the steps taken or planned to prevent recurrence. The permitting authority may waive the written report if the oral report is received within 24 hours.

Sanitary sewer overflows reaching waters of the State are reported under this framework. Do not memorize a spill-volume threshold for the South Carolina exam — the reportability test in the rule is whether the event may endanger health or the environment, not a fixed number of gallons.