A utility that sends compliance samples to an outside laboratory is buying two things: a number and a claim about how that number was produced. The contract usually specifies the first. The second often sits in an accreditation certificate that nobody rereads after the first renewal. For PFAS work, that gap is harder to tolerate than it was, because the analytical question has moved from the technical file into public policy.
Circle of Blue reported on a new study, in a piece dated October 23, 2026, that suggests PFAS contamination in drinking water "may be underestimated." The summary available for this article does not describe the study's methods, so this piece does not assess them. It takes up a narrower question that any municipal manager can act on: does the laboratory on your order hold accreditation for the exact method, sample type, and analyte list you are paying for? The full Circle of Blue report is the place to start if your board wants the study's own framing.
Read the Scope, Not the Logo
An accreditation certificate lists scope: method identifiers, analyte groups, matrices, and sometimes concentration ranges. A laboratory can hold valid accreditation for drinking water metals and still have no scope for a particular PFAS method run on a particular sample type. Ask for the scope document that covers the contract period, then compare it line by line against the methods written into each task order. If an order says "EPA-approved method" without a method number and version, the contract is leaving the choice of method to the laboratory, and the file cannot show which one was used.
Match the Analyte List to the Question
A named-compound list answers only the compounds it names. The scope, the task order, and the final report should agree on which compounds are reported. The contract should also say how the laboratory reports compounds that fall below its reporting limit, because that rule determines what the report can and cannot show. This is a documentation question more than a chemistry question, and it is easy to settle before the first sample is drawn and expensive to settle after the results arrive.
Track Method Changes as Records
Laboratories revise methods, and accreditation bodies update scopes on their own schedules. A revision that changes extraction steps or instrument configuration may not change the name printed on the report, so the utility's file should record the method version used for each sampling event. Ask the laboratory to give written notice of revisions, and file each notice alongside the results it affects. A trend line that changes direction in the same quarter as a method revision needs that notice in front of it before anyone reads the change as environmental.
What the Renewal Should Require
- A current scope certificate attached to the contract file, with its issue date recorded.
- Method identifiers and version numbers named in every task order.
- An analyte list that matches the regulatory or internal purpose of the sampling.
- The reporting limit stated on each report, along with the limit the laboratory achieved for that sample.
- Written notice of method or scope changes during the contract term, sent to a named utility contact.
Limits of This Check
Accreditation confirms that a laboratory was assessed against a standard for particular methods. It does not confirm that a given sample was collected, preserved, or transported correctly, and it does not tell you whether a regulator will accept a result for a compliance purpose. Those questions belong to the sampling plan and to the agency that holds the compliance authority. A scope check narrows the procurement risk and makes the file easier to defend. It does not settle the science, and it should not be presented to a board as if it did.