The Two Million North Carolinians UCMR 5 Never Tested

Introduction

The UCMR 5 dataset behind our dashboard is the best PFAS occurrence picture North Carolina has ever had: 290 public water systems, 70 counties, every result geocoded and comparable. It is also, by design, incomplete. UCMR 5 sampled public water systems — utilities serving more than 3,300 people, plus a representative slice of smaller ones. It did not sample a single private well. In North Carolina, where more than two million residents rely on private wells for drinking water, that means the most comprehensive federal PFAS survey in history bypassed roughly a fifth of the state's population. The map looks complete. It is not.

Why wells are the blind spot

This is not an oversight in the usual sense — it is structural. Private wells are unregulated at the federal level; no agency is required to test them, and no utility is responsible for treating them. The science, meanwhile, says wells deserve more attention, not less:

• Hydrogeology works against well owners. PFAS plumes migrate through shallow aquifers — exactly the zone most domestic wells draw from. A municipal system pulls from deep, blended sources with dilution on its side. A 60-foot domestic well next to a former industrial site or a biosolids application field has no such buffer.
• The Cape Fear lesson. Downstream of the Fayetteville Works facility, some of the highest PFAS exposures documented in North Carolina were in private wells, not utility intakes. GenX and its byproducts showed up in well water at levels that triggered bottled-water provisions and, eventually, whole-house filtration programs. Those wells were found because people got sick of waiting and organized — not because a monitoring rule found them.
• Renters and rural communities carry the risk. Well stewardship — testing, treatment, maintenance — falls entirely on the homeowner. In practice that means it correlates with income and information access, which is another way of saying the exposure burden skews toward the communities least able to absorb it.

What the data we do have implies

Here is the uncomfortable inference from our dashboard: 47 counties have public systems exceeding federal PFAS limits. Public systems draw from the same aquifers and rivers as the private wells around them — often from shallower, less protected zones in the wells' case. Where a utility well field shows PFAS, nearby domestic wells are at minimum worth testing. The county-level patterns on our map are, if anything, a conservative sketch of the true exposure footprint. The real map — the one including two million untested wells — would almost certainly show more red, not less.

What can actually be done

Unlike many PFAS problems, this one has tractable solutions at multiple levels:

1. Test. A certified PFAS panel for a private well costs a few hundred dollars — real money, but orders of magnitude less than the health costs of chronic exposure. North Carolina's PFAS Testing Network and county health departments are the starting points; DEQ maintains guidance on accredited labs.
2. Treat at the tap or the tank. Under-sink reverse osmosis handles drinking and cooking water for a few hundred dollars installed. Whole-house GAC or RO runs into the low thousands — serious money, but comparable to a well pump replacement, and it addresses every tap.
3. Policy. Other states have begun subsidizing private-well testing in PFAS-impacted zones. North Carolina could do the same, targeted by the very occurrence data on dashboards like this one: prioritize testing assistance in the 47 counties with known exceedances, then expand outward. Data-driven triage is exactly what statewide occurrence datasets are for.
4. Disclosure. North Carolina does not require PFAS testing at real-estate transfer for well-dependent properties. It should. A buyer inheriting a contaminated well with no knowledge of it is a preventable failure.

The bottom line

We have built, for the first time, a genuinely statewide picture of PFAS in North Carolina's public water — and it should change how we think about the water we haven't tested. The two million residents on private wells are not covered by federal monitoring rules, federal treatment mandates, or utility public-notification requirements. They are covered, if at all, by their own initiative. Closing that gap — with targeted testing assistance, honest risk communication, and disclosure rules — is the most cost-effective public health move in the PFAS space that nobody is currently making at scale. The data tells us where to start. We should start.