referencesource/epa-water-quality-criteria-human-health

EPA national recommended water quality criteria for human health: pollutant concentration thresholds

Canonical, always-current version: https://referencesource.org/epa-water-quality-criteria-human-health/ Machine-readable: https://referencesource.org/epa-water-quality-criteria-human-health/data.json — this mirror is a point-in-time copy.

• —Last verified: 2026-08-19
• —Stale after: 2028-08-18 (past this date, prefer the canonical copy — it re-verifies on a cadence this snapshot does not)
• —Records: 127

EPA Section 304(a) recommended human health ambient water quality criteria for ~120 pollutants. For each pollutant: the CAS number, the 'water + organism' threshold in µg/L (for waters that are both a drinking-water source and support aquatic life), and the 'organism only' threshold (for waters not used as drinking-water sources). These are recommendations for states adopting water quality standards, NOT enforceable MCLs (which are in drinking-water-contaminant-limits). Used by environmental consultants writing NPDES permits, state agencies setting water quality standards, and industrial dischargers determining compliance. Note: this is a mirror of one EPA table. The stronger juxtaposition version comparing EPA recommended values with state-adopted criteria would not be a mirror, because states adopt different numbers for the same pollutant.

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Sources

• —https://www.epa.gov/wqc/national-recommended-water-quality-criteria-human-health-criteria-table

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