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Natural Resources Extension Program
Testing water
The following
information outlines sample collection methods and sample
types.
What should I sample for:
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If the water is to be consumed by humans, at
minimum sample for: |
- TDS (total dissolved solids)
- Nitrate
- pH
- Fecal Coliform
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Some contaminants may be present only during
part of the year. To assess the year-round safety
of your drinking water, collect the sample when
contaminants are most likely to be present. Coliform
bacteria and nitrates are most likely to be found
during wet weather; late spring and early summer
are the best times to test for these. Pesticides
are likely to be present just after they are applied
- late spring and early summer are the pest times
to test for these, also.
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| Finding
a lab to analyze water: |
- Look in the phone book under laboratories
that specialize in agricultural industry.
- Contact your local County Extension Office
and ask them for labs in your area.
- Contact your local NRCS Office.
- Contact your County and State Health Department.
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IMPORTANT: Contact the
lab that will be running the tests before you start
sampling, to obtain specific sampling instructions.
Most testing laboratories supply their own sample containers
and instructions for collecting, preserving and handling
water samples. The following steps are general sampling
instructions.
General
Sampling Method:
Collecting Samples from Drinking
Water:
- It is best to obtain sample
bottles from the lab you are using, because the sample
bottles need to be sterile. Make sure nothing but
the water to be sampled comes in contact with the
inside of the cap or bottle.
- Flush the water line leading to the tap. Remove
the aerator screen from the faucet and open the tap
to full flow. Let it run until water arrives from
the well (usually signaled by a drop in temperature).
- Reduce the flow to a pencil-sized stream. Open the
container, fill to 1/2 inch of the top and replace
the cap immediately to preserve volatile compounds
in the water and prevent atmospheric contamination.
- Many tests require that the sample be received at
the laboratory within a certain time period to insure
accurate results. Coliform bacteria samples must be
received within 24 hours after collection. If the
sample cannot be mailed or transported immediately,
refrigerate it (do not freeze) and get it to the lab
as soon as possible.
Collecting Samples from Surface
Water (streams, lakes, ponds):
- Follow the steps above.
- Except the source will be different:
- Take sub-samples at several different sampling
points along the surface water source.
- Mix the sub-samples in a clean, sterile container.
The information on this page
was adopted from the Montana State University Publication
"Groundwater, Water Testing Guidelines and Considerations."
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