If funds are low, use a single sample at the point of use (end point) to account for the entire irrigation system. If funds are available or you plan on participating in the cost share program, I recommend a single sample from the water source (wellhead, surface water, etc.) and a single sample at the point of use (end point) for irrigation and wash water. Your results will be representative of the water quality throughout your system. This way you will be able to identify if your water is becoming contaminated through your system, either irrigation lines or at the wash station. If you do find some level of contamination, you can isolate it either to the water source (i.e. crack well casing, inflow from above due to faulty well seal, contaminated runoff, wildlife contamination, etc.) or to the above-ground (i.e. irrigation or wash station) system.
For irrigation water samples
- Run the irrigation system for the amount of time to flush the ‘hold up’ volume of the system plus an additional 5-10 minutes.
- Collect samples from the sprinkler/drip system (not the intake area).
For wash water samples
- When collecting samples from the distribution system tap make sure to remove any attachments, such as aerators (Kitchen faucets with swivel arms are not recommended locations for sampling.)
- Open the tap fully and allow the system to run for at least 10 minutes (or the time to flush out the ‘hold up’ volume) before the sample is taken.
- Slowly fill the container to the line as indicated. (Do not let the container overflow.)
- Tightly cap the container.