An accurate water-quality analysis begins with proper water sampling.
When you’re assessing the quality of your herd’s water supply, take two samples, advises Dave Beede, professor of dairy nutrition at Michigan State University. Take one sample as close to the well (the primary source of the water supply) as possible. Take the second sample after the storage compartment of the reserve tank/pressure tank, or as close to the cows as you can. Avoid sampling from tanks and other water sources that cows come into contact with. This can contaminate the sample.
Submit the sample for a standard lab analysis for “livestock water,” Beede said at the 2012 Tri-State Dairy Nutrition Conference.
If the lab report shows iron concentrations greater than 0.3 parts per million (ppm) or either sulfate or chloride concentrations greater than 250 to 500 ppm, take two more samples and send each to a different certified lab for analysis.
"This may seem like over-kill at the time, but water treatment systems can be a major investment, so it is important to know absolutely for sure that concentrations of a particular analyte are in excess," Beede says.
When collecting water for analysis, label and seal two additional samples in screw-top bottles to serve as back-ups and as a historical record.