4.1 The primary sample should be obtained by one
                           of the following methods:
                        
                        
                        
                        
                           - 
                              
                              
                              
                                 .1 manual valve-setting continuous-drip sampler;
                                 or
                               
- 
                              
                              
                              
                                 .2 time-proportional automatic sampler; or
                               
- 
                              
                              
                              
                                 .3 flow-proportional automatic sampler.
                               
 
                     
                     
                     
                        
                        
                         
                           4.2 Sampling equipment should be used in accordance
                           with manufacturer’s instructions, or guidelines, as appropriate.