At what angle should you hold the bottle while filling it?

When filling a water sampling bottle, it is recommended to hold the bottle at a 45-degree angle. This angle strikes a balance that allows for effective collection of the water sample while minimizing the risk of contamination. Holding the bottle at this angle helps to prevent bubbles from forming in the bottle, which could introduce air and potentially alter the water's chemical composition.

Additionally, a 45-degree angle allows for better control over the stream of water entering the bottle, reducing the chance of oversplashing or contamination from the surfaces around the sampling area. This method is particularly important in preserving the integrity of the sample, as even small contaminants can affect subsequent analyses.

While other angles might not fully account for these concerns, the 45-degree position ensures optimal collection conditions and accuracy in sampling, making it the preferred choice in water sampling techniques.