Taking a Proper Water Sample

Water quality data is only as good as the water samples from which the measurements are taken.  Even the most precise laboratory analysis of a water sample cannot compensate for improper or poorly executed sampling procedures, or for physical and chemical alteration of a sample due to inappropriate sample collection, transport, or storage.
Samples must be analyzed within 48 hours of collection. Samples analyzed between 30 and 48 hours after collection will be flagged to indicate possible invalid results. The shorter the time elapsed between collection and analysis of the sample, the more reliable the results. (The reliability of the results will be improved if shipped with blue ice in an insulated container). Only samples collected in pressure-sterilized containers supplied by Denele Analytical will be analyzed for coliform bacteria. Containers are available at no cost from the lab.

How to take a water sample
* If requesting lead analysis from a tap or drinking water fountain, do not run water through the tap or fountain for at least 8 hours prior to sampling.
* Wash hands with soap and water before collecting sample.
* For bacteria analysis, avoid collecting samples from outside sill-cock, frost-free hydrants, taps with aerators or charcoal filter attachments, or hot water faucets.
* If requesting lead analysis, collect the sample in the special trace metal container from the initial water flow coming out of the faucet (first flow).
* If submitting samples for bacteria analysis, disinfect the faucet with heat or bleach. Do not use heat on plastic or soldered screens.
* Let cold tap run at full force for at least 3 to 5 minutes to clear the line.
* If testing for bacterial analysis, carefully open the lid of the container with the orange “STERILE” label. Do not touch the inside of the container or the lid. Do not lay the open container down.
* Slow the flow of water to a stream free of bubbles and take the sample without turning the faucet on and off.
* Slowly fill the container with water to within ½ inch of the container rim. Do not splash or allow the container to overflow.* Replace the lid.

* Fill the non-sterile container(s) if testing for other parameters (if testing for heavy metals, not including lead, the special trace metal container is also filled at this time).
* Tighten the lids securely on all bottles to prevent them from opening during shipment.

Collecting Samples for Irrigation, 13 Parameters, and Livestock Water Analysis
* Use only the non-sterile container.
* Collect samples after the first irrigation set or cycle has been completed, preferably during the peak of the pumping season
* Allow well to run for 1 to 2 hours prior to sampling.
* Do not collect samples while injecting fertilizer or chemicals.
* New wells should be sampled only after pipe and screen have been installed and after pumping out all water added during the drilling operation.
* Samples from lakes, streams, or ponds should be collected from the surface by pointing the open bottle in the direction from which the water is flowing.