1. What is Water Conductivity and Resistivity?

Water conductivity (σ) measures how well water can conduct an electric current, while resistivity (ρ) is the reciprocal that measures how strongly water opposes electric current. They are inversely related fundamental properties in water quality analysis.

2. How Does the Calculator Work?

The calculator uses the simple equation:

Where:

• \( \rho \) — Resistivity (Ω·m)
• \( \sigma \) — Conductivity (S/m)

Explanation: The equation shows the inverse relationship between conductivity and resistivity in water.

3. Importance of Resistivity Calculation

Details: Water resistivity is crucial for determining water purity, especially in industrial processes, laboratory applications, and semiconductor manufacturing where ultra-pure water is required.

4. Using the Calculator

Tips: Enter water conductivity in Siemens per meter (S/m). The value must be greater than 0. For microsiemens/cm (common unit), divide by 10,000 first (1 S/m = 10,000 μS/cm).

5. Frequently Asked Questions (FAQ)

Q1: What are typical conductivity values for different water types?
A: Ultra-pure water: 0.055 μS/cm (5.5 × 10⁻⁶ S/m), Drinking water: 50-1500 μS/cm (0.005-0.15 S/m), Seawater: ~5 S/m.

Q2: Why is resistivity important in water quality?
A: Higher resistivity indicates purer water with fewer ions. It's critical for applications requiring minimal ionic contamination.

Q3: How does temperature affect conductivity/resistivity?
A: Conductivity increases ~2% per °C rise. Measurements are often standardized to 25°C for comparison.

Q4: What's the relationship between TDS and conductivity?
A: Total Dissolved Solids (TDS) can be estimated from conductivity (TDS in ppm ≈ conductivity in μS/cm × 0.64).

Q5: When is resistivity measurement preferred over conductivity?
A: Resistivity is preferred when dealing with very pure water where conductivity values become extremely small.