Samples must be delivered to the lab within _____ hours to avoid rejection.

Delivering water samples to the laboratory within 30 hours is important for ensuring sample integrity and accurate analysis. This timeframe is based on the stability of various water quality parameters and the potential for changes in the sample that could occur over time.

When water samples are not analyzed within this specified period, there is a risk of degradation due to factors such as bacterial growth or chemical alterations. These changes can lead to erroneous test results, which could ultimately affect decisions regarding water quality and safety.

The specified time limit allows for sufficient processing time while still maintaining the reliability of the analytical results. This is a standard practice in water quality monitoring and testing, reflecting guidelines established by regulatory agencies to ensure that samples represent the actual conditions at the time of collection.