| Value | Category | Cases | |
|---|---|---|---|
| 1 | porous cesspit | 136 | 
                                                                 
                                    
                                    47.7%
                                 
                                                             | 
                                                        
                    
| 2 | Sewage network | 47 | 
                                                                 
                                    
                                    16.5%
                                 
                                                             | 
                                                        
                    
| 3 | tight cesspit | 95 | 
                                                                 
                                    
                                    33.3%
                                 
                                                             | 
                                                        
                    
| 4 | Other | 7 | 
                                                                 
                                    
                                    2.5%
                                 
                                                             |