| Microbiological assesment | Classification system of bacteriological parameters for quality surface water | |||||
| Parameter | Faecal pollution | I low | II moderate | III critical | IV strong | V excessive |
| Total coliforms/100 ml | <500 | >500 - 10,000 | 10.000 - 100,000 | 100.000 - 1,000,000 | >1,000,000 | |
| Faecal coliforms/100 ml | <100 | >100 - 1000 | 1 000 - 10,000 | 10.000 - 100,000 | >100,000 | |
| Intestinal enterococci/100 ml | <50 | >50 - 100 | 100 - 1000 | 1.000 - 10,000 | >10,000 | |
| Parameter | Organic pollution | I low | II moderate | III critical | IV strong | V excessive |
| Heterotrophic Plate Count 22˚C | <500 | >500 - 10,000 | 10.000 - 100,000 | 100.000 - 750,000 | >750,000 | |