| #Q001 | monitoring | operational | guidance | Alternate analytical method validation | drinking water | A jurisdiction could also validate and apply an alternate analytical method that quantifies a minimum of 18 PFAS. | | high |
| #Q002 | monitoring | operational | mandatory | EPA Method 533 MS/MS MRM mode requirement | drinking water | It requires the use of MS/MS in multiple-reaction-monitoring (MRM) mode to enhance selectivity and specificity for compounds of interest. | When using EPA Method 533 for determination of select PFAS in drinking water | high |
| #Q003 | monitoring | operational | mandatory | Separate sample preparation procedures | drinking water | Because they rely on different sample concentration techniques, the 2 methods require separate sample preparation procedures and cannot be combined into a single analysis. | When using both EPA Method 533 and EPA Method 537.1 | high |
| #Q004 | monitoring | operational | recommended | Analytical method selection consideration | drinking water | Utilities should take into consideration the potential sources of PFAS and select a method that will provide analyses that include PFAS that may be present in the drinking water. | | high |
| #Q005 | reporting | reporting | recommended | Total PFAS calculation inclusions | drinking water | Total PFAS should include all PFAS listed in a method and detected in a sample. | | high |
| #Q006 | reporting | reporting | recommended | Summation of values above Method Detection Limit (MDL) | drinking water | Any value above the MDL should be included in the summation for total PFAS, recognizing that a value of zero is assigned for any value below the detection limit. | | high |
| #Q007 | monitoring | treatment | recommended | Maximize PFAS analysis scope | drinking water | Where possible, utilities should strive to analyze as many PFAS as possible to gain a better understanding of the PFAS present in the drinking water in order to inform the selection of treatment that will reduce exposure to the greatest extent possible. | Where possible | high |
| #Q008 | reporting | reporting | recommended | Summation of all detected PFAS | drinking water | Any detected PFAS, from all analyses undertaken, should be summed, and this sum should still not exceed the proposed objective value of 30 ng/L. | | high |
| #Q009 | reporting | reporting | recommended | Handling duplicate PFAS analysis results | drinking water | However, if duplicate analysis occurs, the highest of the duplicate individual PFAS results should be taken for the summation. | If duplicate analysis occurs where there is overlap between methods. | high |
| #Q010 | monitoring | operational | guidance | Augmenting quantitative data with screening assays | drinking water | Data from these assays could be used to augment the data from quantitative methods. | When using TOP assay or TOF analysis screening tools. | high |
| #Q011 | administrative | operational | guidance | Authority method specification | drinking water | Given the overlap between the 2 EPA methods and to avoid duplication, the authorities responsible for drinking water may specify 1 method be used. | To avoid duplication between EPA Method 533 and 537.1 | high |
| #Q012 | monitoring | operational | guidance | Duplicate analysis exemption | drinking water | When more than 1 method is used for the analysis, it is not necessary to do a duplicate analysis where there is overlap between methods. | When multiple analytical methods with overlapping compounds are employed | high |