Infrastructure
The Annual Report Lists Detections, Not Silence: Read the Lab Sheet Behind a PFAS Entry
A blank cell or a not-detected entry describes what a lab could see at one reporting limit on one sampling date, so the sample year and the lab sheet belong in the reading.
Most people read a water utility's annual report the way they skim a menu: they look for the item they care about and move on. In a table of detected contaminants, the item that catches the eye is often a blank cell or a line that says not detected. That line can feel like a verdict. Read the table again, though, and it becomes a record of what a laboratory could see, using a particular method, on a particular sampling date.
A recent report from Circle of Blue, an article dated October 23, 2026, and written by Alissa de Chassey, takes up that gap for PFAS, the family of persistent chemicals that turn up in many water supplies. The headline says contamination "may be underestimated," and the summary focuses on what happens when PFAS concentrations fall below laboratory reporting limits. The reporting is worth reading in full at Circle of Blue's report on a new study of PFAS in drinking water. This column does not restate its findings. It explains the table that most readers will actually hold in their hands.
What a reporting limit does to a table
A reporting limit is the lowest level a laboratory will put a number on for a given method. Below that level, the lab may report the compound as not detected, or it may report a value flagged as an estimate, depending on its procedures and the method it used. Neither entry says the water is free of the chemical. It says the lab's instrument did not register the compound at the level it was set to report. A zero in that setting is a statement about the tool and the threshold as much as it is about the water.
This is why a clean-looking PFAS line deserves a second look. The headline's own wording points at the distance between a number and the water it came from. A report can be accurate about every figure it prints and still leave out compounds that fell below the threshold on the day the sample was taken.
Find the sampling year first
Federal drinking water rules require community water systems to publish an annual water quality report for their customers. The table usually lists each regulated contaminant, the highest level found or the range of results, the limit that applies, and the year the sample was collected. Start with that last column. A PFAS entry from an earlier year describes the water from that year, not the water coming through the pipe this winter.
If the report does not mention PFAS at all, do not assume the answer. Ask whether the system was required to test for them during the period the report covers, whether a test was run, and, if one was run, what the result was. A missing row can mean the system had no requirement to test in that period, or it can mean the question was never asked. The report alone rarely tells you which.
Ask the utility for the lab sheet
The annual table is a compression of the lab's work. The full lab report names the method, the reporting limit for each compound, and the qualifier codes, the short letters that mark a result as estimated or below a threshold. A utility willing to share that sheet makes its summary checkable. A utility that refuses has not necessarily done anything wrong, but it has made the number harder to judge.
Ask for four things: the sampling date, the name of the laboratory, the method used for PFAS, and the reporting limit for each PFAS compound listed. Those four facts turn a single line into a claim you can examine. They also let you compare a table from one year with the next, which is where a change in method or limit often hides.
Private wells sit outside the table
A household on a private well does not receive the utility's annual report, and the table does not describe its water. For a well, the test is the household's own, and the same questions apply to the lab report that comes back. Keep the sheet with the reporting limit printed on it, and keep the sampling date next to it. A later test with no detections tells you what the lab could see at that limit on that day. It does not replace the earlier record, and the two should stay together in the same file.
What to bring to the meeting
Read the report with the lab sheet beside it, then take the questions to the next public meeting or to the utility's office. Ask whether PFAS testing is scheduled, whether the reporting limits used are the lowest the laboratory offers for that method, and whether any results fell below those limits. Ask how the utility will tell customers if a later result changes the picture.
A utility that answers these questions plainly has given you a way to judge its numbers. A utility that cannot name the laboratory or the method has given you a headline without a record behind it. In either case, the annual report is the start of the reading, not the end of it.