| Value | Category | Cases | |
|---|---|---|---|
| 1 | porous cesspit | 61 | 
                                                                 
                                    
                                    21.9%
                                 
                                                             | 
                                                        
                    
| 2 | Sewage network | 58 | 
                                                                 
                                    
                                    20.8%
                                 
                                                             | 
                                                        
                    
| 3 | tight cesspit | 152 | 
                                                                 
                                    
                                    54.5%
                                 
                                                             | 
                                                        
                    
| 4 | Other | 8 | 
                                                                 
                                    
                                    2.9%
                                 
                                                             |