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Calcimator

Water Quality Index (WQI) Calculator

Calculate a composite Water Quality Index (0-100) from dissolved oxygen, pH, BOD, nitrate, phosphate, turbidity, and temperature change.

Inputs

% sat
mg/L
mg/L
mg/L
NTU
°C

Results

Water Quality Index

91.4 / 100

Classification

Excellent

Suitable UsesDrinking (with disinfection), recreation, aquatic life
DO Sub-Index88 / 100
pH Sub-Index98 / 100
BOD Sub-Index90 / 100
Nitrate Sub-Index90 / 100
Turbidity Sub-Index90 / 100
How to Use This Calculator
  1. Measure and enter Dissolved Oxygen (% saturation), pH, BOD5, Nitrate, and Phosphate from water samples.
  2. Enter Turbidity (NTU) and Temperature Change (degrees C above baseline).
  3. Review the Water Quality Index (WQI) — 91-100 is excellent, 71-90 good, 51-70 medium, below 51 is poor.
  4. Check Classification and Suitable Uses to communicate results to stakeholders.
  5. Use the sub-index scores (DO, pH, BOD) to identify the specific parameters driving water quality issues.
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