how to collect samples of your well water

How To Collect Water Samples From Your Well

Follow your lab’s instructions closely, these photos are here to clarify some of those steps. You can also refer to pages 6 and 7 of the CWERC Water Monitoring Guide.

Purge three well volumes of water before collecting samples. To calculate the correct amount of water, see page 7 of the CWERC Water Monitoring Guide.

Gather the sample bottles and paperwork you received from the lab.

Write the required information on each label.

Follow the lab’s instructions to complete each label.

Keep the samples at 4ºC (39º F) by packing the cooler with bags of ice.

Use more ice if your samples will be shipped to the lab.

Collect your first sample while wearing powder-free latex gloves.

Put each sample on ice in the cooler immediately.

Check each label as you continue to collect samples.

Use the correct vial for each sample, as some are light-sensitive.

Use small vials for collecting BTEX samples.

Fill BTEX samples to the top to make sure there aren’t any air bubbles.

Follow the lab’s sampling protocol to collect methane samples.

Make sure the methane samples do not contain any air.

Include the temperature blank and two spikes to verify shipping temperature and lab accuracy.

Pack the temperature blank into the middle of the cooler so it maintains the central temperature.

Pack a bag of ice on top of the samples.

Complete the sample paperwork and chain of custody form, and seal these documents in a plastic bag.

Return the cooler with samples and documentation to the lab.

Learn more about testing your well water quality at CWERC.Colorado.edu where you can download the guide, worksheets and additional materials.

If you have questions about using this guide or testing your well water, please email CWERC at

cwerc@colorado.edu.