What needs to be done to sample sites to ensure water quality?

To ensure water quality at sampling sites, it is essential to remove potential contamination sources. This action minimizes the risk of pollutants or harmful substances entering the water supply, thereby maintaining the integrity of the samples collected for testing. Contaminants can come from various sources, including runoff, industrial discharges, or nearby agricultural activities, and their removal helps to secure an accurate representation of the water's quality.

By eliminating these sources, operators can help prevent interference in the sampling process, ensuring that the water quality assessments reflect the true state of the water without external influences. This step is a fundamental practice in water quality management, as it directly impacts the reliability of testing results used for regulatory compliance and public health protection.

While options like shutting off public access and conducting regular maintenance checks may contribute to overall management practices, they do not specifically address the need to mitigate contamination at sampling sites. Increasing water temperature could potentially worsen water quality by encouraging algal growth or increasing the solubility of certain pollutants, thus it is not a suitable action in this context.