Continue the washing, agitation and decantation until the wash water is clear.

• A. True
• B. It is only until the first rinse
• C. It varies by sample size
• D. False

Answer: (A)

Continuing washing, agitation, and decantation until the wash water is clear ensures that most of the fines and surface coatings are removed so the test results reflect the material itself, not dirt or dust carried by the water. Turbidity means suspended solids are still present; when the water runs clear, it indicates those fines have been largely removed and the sample is representative for accurate gradation, absorption, or specific gravity measurements. Stopping after only the first rinse can leave fines that skew results, whereas washing until the water is clear provides a cleaner, more reliable sample for testing.