Total Dissolved Solids from Conductivity

Total dissolved solids estimated from a conductivity reading.

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Details, formula, and sources

TDS (mg/L) = k x EC (uS/cm at 25 C), k commonly 0.55-0.75 (default 0.65). 1000 uS/cm -> 650 mg/L, with a 550-750 band from the k range so it is not read as exact. An estimate, not a gravimetric TDS; calibrate k to a lab result. The operator of record governs.

tds_mgl = k_factor x conductivity_us_cm; k commonly 0.55-0.75 (default 0.65).

Total dissolved solids from electrical conductivity (Standard Methods 2510), by name.

The TDS = k x EC correlation is a standard published water-quality relation; the k factor is calibrated to the specific water.

Estimate. Operator of record and primacy agency govern.

Field names used by the API: conductivity_us_cm, k_factor, tds_mgl

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