Water Sampling Procedures

For water quality analysis to be meaningful, the following general rules apply when collecting a representative water sample:

• Use a clean, uncontaminated, sealable and non-breakable (plastic ideal) bottles that can hold at least 250ml of water.
• Rinse the container at least twice with the water from the source that will be analysed.
• To best represent the water quality that will be applied to the crop it is advised to collect the sample from pumping station outlet to represent the water being pumped through the irrigation system.
• Allow the pump to run for several minutes before sample collection to improve sample representativeness.
• Where water samples are to be collected from dams/ponds/rivers/canals then it is important to adhere to the following guidelines:
  • Avoid sampling close to the edge of an open water body such as a river or dam.
  • Collect water as close as possible to the intake (abstraction point) of irrigation water.
  • Collect the sample from at least 0.3 m (30cm) below the water surface.
  • It is usually best to collect several samples and mix these to produce a single composite sample.
• Fill the container to the top (to minimise headspace) and seal the container immediately.
• Attach all relevant information required from the testing laboratory including the annual rainfall and irrigation amounts and label samples clearly with markings that will not readily degrade or be rubbed off.