Water Quality Index Calculator

ECOLOGY CALCULATOR Water Quality Index A precise tool.
📖
What is the Water Quality Index & How does it work?

The Water Quality Index (WQI) is a single number that summarises the overall condition of a water body by integrating multiple physicochemical parameters. It helps managers quickly assess whether a water source meets regulatory standards or requires remediation.

Each measured parameter—such as dissolved oxygen, pH, biochemical oxygen demand, nitrates, and turbidity—is first converted into a sub‑index (Qi) that reflects its relative contribution to water quality. These sub‑indices are then weighted (Wi) according to their ecological importance before being combined into the final index.

WQI = frac{sum (Q_i times W_i)}{sum W_i}
Q_i = sub‑index for parameter i, W_i = weight for parameter i

The resulting WQI typically ranges from 0 (poor quality) to 100 (excellent quality). Values are interpreted using classification bands that guide policy decisions, public health advisories, and conservation actions.

⚙️
Parameters
Result —
❓
Frequently Asked Questions
How do I calculate the Water Quality Index?
Measure key parameters like dissolved oxygen, pH, BOD, nitrates, and turbidity. Convert each to a sub-index, then weight and average them.
What does a high WQI indicate?
A high Water Quality Index indicates better water quality, suggesting the water body meets or exceeds regulatory standards.
How often should I calculate the WQI?
It depends on local regulations and the importance of monitoring. Monthly checks are common for regular assessment.
What parameters are included in the WQI calculation?
Common parameters include dissolved oxygen, pH, biochemical oxygen demand (BOD), nitrates, and turbidity.
How does weighting affect the WQI?
Weighting reflects the relative importance of each parameter. More critical factors are given higher weights to influence the overall index more significantly.
What is the range of the Water Quality Index?
The WQI typically ranges from 0 (poor quality) to 100 (excellent quality), though scales can vary based on local standards.
Can I use this calculator for any water body?
Yes, the Water Quality Index is applicable to various types of water bodies including rivers, lakes, and reservoirs.

Results are for informational purposes only and do not constitute professional advice.