PFAS and Home Water Filtration: What Fairfax Water Reports

Start with what the utility publishes

The most useful thing about this topic locally is that you do not have to speculate. Fairfax Water — which describes itself as the largest water utility in Virginia, serving nearly two million people from two major treatment plants — publishes its PFAS monitoring results and says it has been proactively monitoring for PFAS in its water sources and sharing that data since 2021.

What it currently reports, by source:

• Potomac River source (Corbalis Treatment Plant and the Washington Aqueduct) — finished water consistently shows PFAS levels below the EPA’s maximum contaminant level of 4.0 parts per trillion, often at non-detectable levels.
• Occoquan Reservoir source (Griffith Treatment Plant) — some samples have slightly exceeded the MCL for PFOA and PFOS, with all other regulated PFAS within acceptable limits.

On the regulatory side, Fairfax Water notes that the EPA finalised National Primary Drinking Water Regulations for six PFAS on 10 April 2024, and states that it is committed to meeting these standards by the compliance date of 2029, evaluating treatment processes including granular activated carbon and ion exchange.

Both the source data and the report are updated periodically, so check the utility’s current page rather than relying on any summary — including this one.

What PFAS are

Fairfax Water describes PFAS as a large group of over 10,000 human-made chemicals used in industrial applications and consumer products since the 1940s for their ability to repel water, oil and stains, and notes they are often called "forever chemicals" because they are persistent in the environment and in the human body. It also notes that drinking water is estimated to account for about 20% of total PFAS exposure for most people, though this varies.

That last figure is a useful piece of proportion, and we will leave the health questions to the agencies whose job they are: the EPA and the Virginia Department of Health both publish on PFAS, and Fairfax Water links to both.

Point-of-use versus whole-home treatment

These are different tools for different jobs, and the distinction is the practical heart of the decision.

Point-of-use

Treats water at one fixture — typically an under-sink system or a dedicated drinking-water tap. Because it treats a small volume, the media can be more capable per gallon, and because it only handles drinking and cooking water, cartridges last longer relative to what they are asked to do. If the goal is drinking-water quality, this is usually the proportionate answer.

Point-of-entry (whole-home)

Treats water where it enters the house, so every tap, shower and appliance gets it. This is the right choice when the issue affects the whole house — sediment, chlorine taste everywhere, or hardness that is scaling your water heater and fixtures. It is a larger system handling far more volume, which affects both the equipment and the service interval.

A great many households in Northern Virginia are best served by point-of-use treatment for drinking water and, separately, softening for hardness — those being two genuinely different problems. Our guide on whether you need a water softener covers the hardness side.

Certification is the whole thing

This is the part worth being firm about. A filter reduces what it has been independently certified to reduce, and nothing else. Certification is specific to the contaminant: a system certified for chlorine taste and odour tells you nothing whatsoever about PFAS.

Fairfax Water’s advice to customers is exactly this — use only filters certified to reduce PFAS, and maintain them as recommended.

So when you are evaluating a system, the question is not "does this remove PFAS" but "what is this certified to reduce, under which standard, and does that certification name the contaminant I care about". Ask for the certification documentation. Any supplier who cannot produce it, or who answers with marketing language instead, has answered the question.

We hold ourselves to the same rule. We will not tell you a system removes a contaminant unless its certification supports that exact claim, and we would rather show you the documentation than have you take our word for it.

Maintenance is not optional

Fairfax Water makes a point that is easy to miss: treatment systems can capture PFAS in filters but do not destroy the chemicals, and those filters must be safely disposed of.

The practical implication is that a cartridge past its service life is not a filter that has become neutral. It has stopped delivering the reduction you installed it for, while you continue to assume it is working. The service interval is part of the product, and an installation that makes changing cartridges awkward is an installation that will not be maintained. That is why bypass valves and accessible placement matter more than they sound like they should.

Being sceptical of the sales pitch

Water treatment attracts a particular kind of selling — a free in-home "test", an alarming result, and a same-day discount. A few things are worth holding onto:

• Your utility already publishes monitoring data and an annual water quality report, free and independent of anyone selling equipment. Start there.
• A test administered by the company that profits from the result is not an independent test.
• Hardness, sediment, taste and specific contaminants are four different problems. A system sold as solving all of them deserves scrutiny.
• The purchase price is not the lifetime cost. Ask what the media or cartridges cost and how often they are due.

Fairfax Water also notes, on the subject of what actually helps, that the most effective solution is to stop PFAS at their source — and that it is pursuing source-water protection, advocacy and legal action against manufacturers alongside treatment. Home filtration is a reasonable personal step, taken with clear eyes about what it does.

If you want a system installed

We install both whole-home and point-of-use filtration, we will tell you when point-of-use is the more sensible answer, and we will match certification to the claim rather than the other way round. If your actual problem turns out to be hardness rather than a contaminant, we will say so — softening is a different piece of equipment.

Sources

• Fairfax Water — Facts About PFAS — Fairfax Water
• U.S. EPA — PFAS — U.S. Environmental Protection Agency
• Virginia Department of Health — PFAS in drinking water — Virginia Department of Health