Which type of faucet should never be used for sampling?

When it comes to proper sampling techniques in water quality assessment, using the right type of faucet is crucial to ensure accurate and uncontaminated water samples. A kitchen sink faucet that swivels can potentially allow for the collection of water that has been stagnant in the system, where contaminants may have accrued, thus affecting sample integrity. Outdoor faucets that drip may also introduce issues, as the dripping can lead to water that has remained in contact with the faucet surfaces, causing contamination from the external environment or stagnant water sources.

By selecting "both kitchen sink faucet that swivels and outdoor faucet that drips" as the correct answer, it highlights the principle that faucets with such characteristics pose a risk to obtaining reliable samples. Using faucets that are not designed for sampling can lead to inaccuracies in testing results, diminishing the effectiveness of water quality monitoring. Proper sampling procedures typically recommend using dedicated sampling spouts or taps that are less likely to introduce contaminants.

This understanding is vital for water operators to ensure the quality of the water being tested and to follow best practices in sampling methodologies.