What type of test should be conducted biannually on wells deeper than 50 feet?

Bacteriological tests should be conducted biannually on wells deeper than 50 feet to ensure the safety and quality of the water. These tests are critical because they detect harmful bacteria and pathogens that can potentially contaminate the water supply. Bacteriological contamination can arise from various sources, including surface water runoff or improper well construction, and it may pose serious health risks if consumed.

Conducting these tests every six months ensures that any contamination issues are identified and addressed promptly, maintaining the safety of drinking water. This routine testing is especially important for deeper wells, which may have different contamination dynamics compared to shallower sources. Regular monitoring helps in sustaining public health and meets regulations and best practices in water quality management.

Other types of tests, while also important, do not specifically focus on the biological safety of the water supply.