1.4 Classifying Drinking Water Facilities: Rating Values, Classes & Required Operators

1.4 Classifying Drinking Water Facilities: Rating Values, Classes & Required Operators

Every North Carolina public water system is told, in writing, what class its facilities are (18D .0401). That classification is not a judgment call — it is arithmetic performed under 15A NCAC 18D .0203, and it determines the grade of certificate the operator in responsible charge must hold.

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Step 1 — Add up the rating values (18D .0203)

The rule lists point values for every source, process, and monitoring feature. Representative values:

Pumping and storage features add smaller values (raw and finished pumping 3 each, elevated storage 2, hydropneumatic 2).

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Step 2 — Convert points into a class (18D .0205(a))

   Class C ................ 1 to 50 points
   Class B ................ 51 to 110 points
   Class A ................ over 110 points

One special case overrides the arithmetic: a non-community public water system whose only treatment is hypochlorite solution is classified Class D-Well. That is why a small church or campground well with a chlorine pump needs a Grade D-Well ORC rather than a Grade C operator.

Worked example. A town treats an impounded stream (7) with alum coagulation (10), mechanical rapid mix (4), standard-rate sedimentation (5), gravity dual-media filtration (12), gas chlorine disinfection (10), fluoride saturator (8), caustic pH adjustment (10), raw and finished pumping (3 + 3), one elevated tank (2), and on-site MF bacteriological, chlorine titrator, pH meter, and turbidity testing (5 + 3 + 2 + 1). Serving 9,000 people adds 9 points; a 2 MGD capacity adds 2. Total = 96 points → Class B, so the ORC must hold at least a Grade B-Surface certificate.

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Step 3 — Classify the distribution system separately (18D .0205(b))

Distribution classification applies to community and non-transient non-community systems, and the class is the greater of the treatment plant class or the class from this table:

A "fire protection system" is defined in 18D .0105(4) as dry or wet sprinkler systems or fire hydrant connections to the distribution system — so adding hydrants to a 600-connection system jumps it from Class C to Class B.

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Step 4 — Cross-connection control classification (18D .0205(c))

The Cross-Connection Control classification applies to any distribution system required to have five or more testable backflow prevention assemblies installed in accordance with 15A NCAC 18C .0406(b). Those systems must designate an ORC holding a valid Cross-Connection Control certificate (18D .0206(d)) and must keep the program records listed in 18C .0406(b)(6).

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Step 5 — Match the operator to the class

• Each classified treatment facility that alters the physical, chemical, or microbiological characteristics of the water must have a certified ORC (18D .0206(a)).
• Community and non-transient non-community systems must also have an ORC for the distribution portion, holding a distribution certificate equal to or above the distribution class. A system with 100 or fewer connections is exempt if it already has a treatment ORC, and a D-Distribution-only system may use a certified distribution, well, or surface operator (18D .0206(c)).
• Transient non-community systems with only ultraviolet disinfection or softening as treatment need no ORC at all (18D .0206(f)).

[!WARNING] Classification changes when the plant changes. Adding an ozone contactor, switching from hypochlorite to gas chlorine, or growing past 3,300 connections changes the point total or connection count and can force the system to hire or promote a higher-grade ORC. Owners must notify the Board in writing within 10 days of a vacancy that puts them out of compliance (18D .0206(a)).