Records of turbidity analysis must be kept for at least how many years?

• A. 2 yrs
• B. 5 yrs
• C. 8 yrs
• D. 12 yrs

Answer: (B)

Keeping turbidity analysis records for five years is required. Turbidity data are essential for showing that water treatment and disinfection are performing properly, and regulators need to verify compliance and investigate any issues over a substantial period. Maintaining a five-year record also supports trend analysis, calibration checks, and audits. Shorter retention (like two years) wouldn’t meet typical regulatory expectations, while longer periods (eight or twelve years) exceed the minimum standard.