Well Water Sampling Instructions by W. Adam Sigler and Jim Bauder Montana State University Extension Water Quality Program Department of Land Resources and Environmental Sciences

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Although sampling your well water for laboratory analysis is a relatively simple task, several steps must be taken to ensure accurate results.

What to do:

1. Determine which parameters you want to test for.
2. Contact a certified laboratory to request sample bottles.
3. Choose a day to sample. The best days to sample are Monday or Tuesday, as this allows time for shipping and testing at the lab before the weekend. The sample will need to be mailed the same day it is collected. Strictly speaking, the sample should be at the lab within 24 hours of collection.
4. Choose a location to sample your water. If you don’t have any water treatment devices, such as a water softener or a reverse osmosis filter, take the sample from a cold water tap where you get your drinking water. If possible, choose a non-leaking, non-swivel, non-mixing faucet.
   
   If you do have treatment devices on your water system, you need to decide what you want to test. Do you want to know about your source water quality or the water you are actually drinking? A water softener will replace some of the calcium and magnesium in your water with sodium and/or potassium. A filtration system will remove some of the contaminants from your water. If you want to sample what you are using, simply get the sample from the tap you get drinking water from. If you want to sample your source water, locate a faucet which is attached to the water line before the treatment system.
5. Remove any faucet attachments and aeration screens and disinfect the mouth of the faucet with rubbing alcohol or bleach.
6. Turn on the cold water and let it run to waste for 2 to 3 minutes to flush the water out of the pipes. Turn the faucet down to a pencil size stream of water and fill sample bottle(s). To prevent contamination of your sample, wash your hands before sampling and do not touch the inside of the bottle or lid.
7. Ship your samples to the lab the same day.