| Value | Category | Cases | |
|---|---|---|---|
| 1 | porous cesspit | 61 | 
                                                                 
                                    
                                    21.9%
                                 
                                                             | 
                                                        
                    
| 2 | Sewage network | 63 | 
                                                                 
                                    
                                    22.6%
                                 
                                                             | 
                                                        
                    
| 3 | tight cesspit | 148 | 
                                                                 
                                    
                                    53%
                                 
                                                             | 
                                                        
                    
| 4 | Other | 7 | 
                                                                 
                                    
                                    2.5%
                                 
                                                             |