| Class | Status | Qualification |
| 0 - 25 | Excellent | Clean water, excellently suitable for drinking |
| 26 - 50 | Good | Suitable for drinking |
| 51 - 75 | Medium “marginal” | Modestly suitable for drinking |
| 76 - 100 | Poor | Unsuitable for drinking, minor treatment (purification) required before usage |
| >100 | Very poor | Unsuitable for drinking, Appropriate treatment required before usage or seek alternative sources of supply |