State the decision threshold
Provide the permit or project criterion and its units. The laboratory needs to know the required result boundary before selecting a scope that can support it.
Separate analytical terms
Detection and reporting limits serve different roles. Matrix effects, preparation and dilution can influence the limits achievable for a particular sample.
Read a below-limit result correctly
A reported result below a stated limit is bounded by that limit. It is not an unlimited statement that no analyte exists in the source.
Keep units aligned
Check mass, volume, nitrogen or compound basis and any sample fraction before comparing a result with a criterion. Numerically similar values can describe different measurements.
Related testing & guidance
Technical & service references
Vanguard water-testing menuEPA: Clean Water Act method questionsEPA: Drinking-water analytical methodsSource review: November 8, 2026. The agreed method and project scope govern the testing.