PFOA and PFOS in Birmingham water: the honest numbers

PFAS coverage tends to arrive in two flavors: alarming, or dismissive. If you're deciding whether to spend money, the useful version sits in between.

Here are Birmingham's published numbers, what the standards are, and what genuinely does something about it.

What PFAS are

Per- and polyfluoroalkyl substances are a large family of synthetic compounds used since the 1940s in non-stick coatings, stain-resistant fabrics, food packaging and firefighting foams. The carbon-fluorine bond that makes them useful also makes them extremely persistent — hence "forever chemicals."

Two are most closely regulated in drinking water: PFOA and PFOS.

Birmingham's published results

From the Central Alabama Water (formerly Birmingham Water Works) 2026 Annual Water Quality Report, covering 2025 monitoring:

Two readings, both accurate, and you should hold them at the same time.

The results are measurable, and PFOS at the top of its range reaches 95% of the limit. That is a thin margin. Today's water is compliant — the margin is simply narrow enough to be worth knowing about.

For scale: a part per trillion is roughly one drop in twenty Olympic swimming pools. The fact that we can measure these compounds at all is a recent analytical achievement.

Where they come from

PFAS in surface water generally arrives from industrial discharge, historical firefighting foam use, wastewater treatment effluent and landfill leachate. Birmingham draws entirely from surface water — the Cahaba, Little Cahaba, Lake Purdy, Inland Lake and the Black Warrior basin — and surface water in any industrialized region tends to carry a measurable PFAS load.

Conventional drinking water treatment is built for turbidity and pathogens, and coagulation, sedimentation, filtration and chlorination do that job well. PFAS pass through largely unaffected.

What actually reduces them

This is where precision matters more than anywhere else on this site, so I'll be blunt about the limits of each technology.

Reverse osmosis — the right tool

RO is a recognized and effective technology for PFAS reduction, and it's what we'd recommend.

With one critical qualification: baseline NSF/ANSI 58 certification covers total dissolved solids reduction. A PFOA or PFOS reduction claim is a separate claim that must appear on that specific product's certification listing. "NSF certified" on a box tells you a product is listed; the listing itself tells you what for.

The EPA says exactly this in its guidance on identifying certified PFAS filters: look for certification under NSF/ANSI 53 or 58 for PFAS reduction, and check the certifier's listing to confirm the product treats the compounds you care about. Five certifiers are recognized — NSF, CSA Group, IAPMO R&T, UL and WQA.

We describe what a listing supports: reduction of named compounds, under a named certification. For any system we propose, the listing number comes with it.

What the other options actually do

The regulatory picture is still moving

The EPA finalized National Primary Drinking Water Regulations for several PFAS compounds in 2024, setting enforceable limits of 4.0 ppt for PFOA and PFOS, with compliance deadlines later this decade. Since then the agency has signaled reconsideration of parts of the rule.

We're flagging it because the ground is still moving. If your decision turns on a specific regulatory threshold, check the current federal position directly — it may have moved since this was written.

So should you do something?

Here's the framing we'd use ourselves.

You have time here. The water is compliant, the levels are low in absolute terms, and it carries no public health advisory.

At the same time, the results are measurable, PFOS sits close to its limit, and these compounds are persistent and bioaccumulative by design. Reasonable people weigh that differently, and both conclusions are defensible.

The exposure route that matters here is ingestion — drinking and cooking. That makes PFAS a point-of-use problem with a point-of-use answer, at $995 rather than the several thousand a whole house costs.

If a whole-home system is quoted to you on the strength of PFAS, ask which certification listing supports that claim for the specific equipment proposed. That one question settles it.