When can percent moisture be approved to be used with a gauge?

• A. When the gauge and material has been approved
• B. When the gauge is calibrated
• C. When moisture is within specification
• D. When testing is complete

Answer: (A)

Percent moisture readings using a gauge are only approved when the gauge and the material have been approved for use together. This formal approval ensures that the device has been validated for that specific soil type and moisture range, so the readings reliably reflect actual moisture content in the field. Calibration is important for accuracy, but it doesn’t substitute for the approval of the gauge–material pairing. Merely having moisture within specification or finishing testing doesn’t grant authorization to use the gauge—the approval criterion specifically covers the compatibility of the gauge with the material.