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C A RY, N O RT H C A R O L I N A A N N U A L WAT E R Q U A L I T Y R E P O R T 2 0 2 3 10 D I S I N F E C TA N T R E S I D U A LS Chloramine, a compound of chlorine and ammonia, is used to disinfect the water throughout the year except in the spring when we switch to chlorine. This ensures a high level of disinfection. SUBSTANCE (UNIT OF MEASURE) YEAR SAMPLED HIGHEST LEVEL ALLOWED (MRDL) HIGHEST LEVEL GOAL (MRDLG) AMOUNT DETECTED RANGE VIOLATION TYPICAL SOURCE Chlorine (ppm) 2023 4 (running annual average) 4 2.19 (running annual average) 0.52–3.53 (individual sites) No Water additive used to control microbes Chloramines (ppm) 2023 4 (running annual average) 4 2.91 (running annual average) 1.12–4.00 (individual sites) No Water additive used to control microbes D I S I N F E C TA N T BY P R O D U C T S Disinfectants such as chlorine, chloramines, and ozone react with natural organic matter and/or bromide to form different disinfection byproducts. SUBSTANCE (UNIT OF MEASURE) YEAR SAMPLED HIGHEST LEVEL ALLOWED (MCL) HIGHEST LEVEL GOAL (MCLG) AMOUNT DETECTED RANGE VIOLATION TYPICAL SOURCE Bromate (ppb) 2023 10 (running annual average) 0 5 (running annual average) 1–6 (individual measurements) No Byproduct of drinking water disinfection SUBSTANCE (UNIT OF MEASURE) SAMPLE LOCATIONS YEAR SAMPLED HIGHEST LEVEL ALLOWED (MCL) HIGHEST LEVEL GOAL (MCLG) AMOUNT DETECTED (HIGHEST LRAA) RANGE (INDIVIDUAL MEASUREMENTS) VIOLATION TYPICAL SOURCE Trihalomethanes (THMs) (ppb) B01 B02 B03 B04 B05 B06 B07 B08 2023 80 N/A 47 27–50 27–51 27–49 27–54 27–53 27–49 26–56 25–52 No Byproduct of drinking water disinfection Haloacetic Acids (HAAs) (ppb) B01 B02 B03 B04 B05 B06 B07 B08 2023 60 N/A 21 14–22 16–29 12–33 14–30 4–34 13–33 11–30 5–30 No Byproduct of drinking water disinfection

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