Water Nitrate
Benchmark Value
Scoring Curve
This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context. The scoring engine uses 5 benchmarks together — the OptimalRange form drives the primary score, while 4 guard(s) constrain the result.
Contributing Benchmarks
Evidence & Context
Lower Critical Threshold: While nitrate is essential for aquatic life, a critically low level for ecological health in receiving waters from managed agricultural land is unlikely to be a primary concern compared to excess nitrate. Natural background levels in pristine systems can be 0.01 0.02 mg/L NO3 ; below this, N-limitation might occur in truly oligotrophic systems, but this is not typically an issue in agricultural settings.
Lower critical threshold of water nitrate concentration below which nitrogen limitation might occur in aquatic ecosystems.
This benchmark represents the lower critical threshold for nitrate concentration below which nitrogen limitation might occur in aquatic ecosystems, though it is not typically a concern in agricultural settings.
Natural background levels in pristine systems can be 0.01 0.02 mg/L NO3 ; below this, nitrogen limitation might occur in truly oligotrophic systems.
Supporting Sources (3)
Additional references from the underlying research that informed this benchmark.
Hickey, C. (2002). Nitrate guideline values in ANZECC 2000. Memorandum MFE02237 prepared for Ministry for the Environment (New Zealand). NIWA Client Report: HAM2002-126.
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Palaeovalley Groundwater Resources in Arid and Semi-Arid Australia - Geoscience Australia, accessed July 31, 2025,
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webcat.niwa.co.nz, accessed May 11, 2025,
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