No | WQI Range | Quality score | Grades |
1. | 0 - 25 | Excellent | A |
2. | 25 - 50 | Good | B |
3. | 50 - 75 | Fair | C |
4. | 75 - 100 | Poor | D |
5. | 100 - 150 | Very bad | E |
6. | Above 150 | Unfit For Drinking | F |