| Value | Category | Cases | |
|---|---|---|---|
| 1 | porous cesspit | 91 | 
                                                                 
                                    
                                    33.6%
                                 
                                                             | 
                                                        
                    
| 2 | Sewage network | 40 | 
                                                                 
                                    
                                    14.8%
                                 
                                                             | 
                                                        
                    
| 3 | tight cesspit | 113 | 
                                                                 
                                    
                                    41.7%
                                 
                                                             | 
                                                        
                    
| 4 | Other | 27 | 
                                                                 
                                    
                                    10%
                                 
                                                             |