Most groundwater thresholds are Upper limits: a contaminant concentration must stay below the threshold or an exceedance is flagged. Lower thresholds are less common but apply in cases where a minimum concentration must be maintained, such as a disinfectant residual or a treatment performance criterion. Knowing the ThresholdDirection is essential for the exceedance detection logic to produce correct compliance results.
Technical section
Data model, API, and internals — visible to developers.