How often must a surface water system be sampled for inorganic chemical contaminants, such as chromium, cyanide, fluoride and mercury?

• A. Every 6 months
• B. Every 3 years
• C. Annually
• D. Every 2 years

Answer: (C)

Monitoring inorganic contaminants in surface water follows an annual schedule to reliably track water quality without overburdening operations. For contaminants like chromium, cyanide, fluoride, and mercury, the regulatory framework typically requires sampling once per year to verify ongoing compliance with primary drinking water standards. This frequency provides a consistent data set to detect any changes in source water or treatment effectiveness while keeping sampling efforts reasonable. Sampling more often (every six months) isn't generally required unless there are special circumstances, and waiting several years could miss important fluctuations in contaminant levels. So, yearly sampling is the standard approach.