Which technique is recommended for properly collecting water samples?

Letting the water run for 2-3 minutes is recommended for properly collecting water samples because this practice helps ensure that the sample reflects the quality of the source water as it exists in the environment, rather than being influenced by stagnant water or contaminants that may be present in the plumbing system. Running the water flushes out any potential contaminants that could have accumulated in the pipes since the last use, providing a more representative sample of the water quality.

In contrast, using a bucket to scoop water may introduce contaminants from the bucket itself or could result in an unrepresentative sample if the water has been stagnant. Tapping the faucet briefly is often ineffective in clearing stagnant water, and collecting water at the first flow does not allow for the necessary flushing that ensures contaminants are removed, leading to a sample that may not accurately reflect the source’s quality. Thus, running the water for a short period before collecting the sample is an essential step in obtaining reliable water quality data.