Water Quality Index Calculator

Enter your water readings — Temperature, BOD, TSS, Dissolved Oxygen, and Conductivity — and the Water Quality Index Calculator computes your overall ISQA score alongside individual sub-scores for each parameter.

°C

Water temperature in degrees Celsius

mg/L

Biological oxygen demand in milligrams per liter

mg/L

Total suspended solids in milligrams per liter

mg/L

Dissolved oxygen concentration in milligrams per liter

μS/cm

Electrical conductivity in microsiemens per centimeter

Results

Water Quality Index (ISQA)

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Temperature Index

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BOD Index

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TSS Index

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DO Index

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Conductivity Index

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Water Quality Rating

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Water Quality Parameter Indices

Frequently Asked Questions

What is the Water Quality Index (ISQA)?

The ISQA (Simple Water Quality Index) is a numerical value that represents overall water quality based on five key parameters: temperature, BOD, TSS, dissolved oxygen, and conductivity. Higher values indicate better water quality.

How is the Water Quality Index calculated?

The ISQA is calculated by first determining individual index values for each parameter, then using the formula: ISQA = Temperature Index × (BOD Index + TSS Index + DO Index + Conductivity Index).

What does BOD measure in water quality?

BOD (Biological Oxygen Demand) measures the amount of oxygen consumed by bacteria and other microorganisms while decomposing organic matter in water. Lower BOD values indicate better water quality.

Why is dissolved oxygen important for water quality?

Dissolved oxygen is essential for aquatic life survival. Higher DO levels indicate healthier water that can support fish and other organisms, while low DO levels suggest pollution or excessive organic matter.

What do TSS measurements tell us about water quality?

Total Suspended Solids (TSS) measure particles floating in water that make it cloudy or turbid. High TSS levels can indicate erosion, pollution, or poor water treatment, affecting both water quality and aquatic ecosystems.

How does conductivity affect water quality assessment?

Conductivity measures water's ability to conduct electrical current, which relates to dissolved salts and minerals. Moderate conductivity is normal, but very high or low values can indicate pollution or other water quality issues.

What is considered good water quality based on the index?

Generally, higher ISQA values indicate better water quality. Values above 80 typically represent excellent quality, 60-80 is good, 40-60 is fair, and below 40 indicates poor water quality requiring attention.

How often should water quality be tested?

Testing frequency depends on the water source and use. Drinking water should be tested annually, while surface waters may need monthly or seasonal testing. Areas with known contamination risks should be tested more frequently.

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