Determination of a physical or chemical parameter in groundwater may be by chemical analysis of a sample or by field measurement by an instrument. Any field measurement of a groundwater parameter using instrumentation must be done using methods and instruments that yield a measurement that is at least equivalent in quality and sensitivity as a measurement determined by chemical analysis.

Source Note: The provisions of this §331.87 adopted to be effective March 12, 2009, 34 TexReg 1638