Methods of Sampling:

When samples are collected from a river or stream, the sampling point should be from top to bottom in the middle of the stream.

To collect sample from wells, the well has to be pumped for sufficient time to ensure that the sample represents the ground water source.

Methods of sampling depend on the type of equipment available, the nature of tests and purposes for which the results of the analysis are to be utilized. Following two types of samples procedures are followed.

(a) Grab or catch sampling.

(b) Composite samples.