PFAS 'Forever Chemicals' in Drinking Water: What South Dakota Homeowners Need to Know

The three letters PFAS have been in the news constantly for the last few years, and for good reason. In April 2024 the EPA finalized the first-ever legally enforceable federal drinking water limits for six of these compounds, kicking off a nationwide monitoring and remediation program that will run for decades. For homeowners the news has been confusing at best and alarming at worst. What are PFAS, really? Are they in Sioux Falls water? And do you actually need to do anything at home?

Here's a plain-English guide.

What PFAS are and why they're everywhere

PFAS stands for per- and polyfluoroalkyl substances — a family of over 12,000 synthetic chemicals invented in the 1940s. They share a carbon-fluorine bond that is one of the strongest in organic chemistry, which is exactly what makes them useful (they resist heat, oil, water, and stains) and exactly what makes them a problem (they don't break down in the environment, or in you). Hence the nickname 'forever chemicals.'

You've used them today, whether you know it or not. PFAS are in nonstick cookware, waterproof jackets, stain-resistant carpet, food packaging (especially fast-food wrappers and microwave popcorn bags), dental floss, cosmetics, and firefighting foam. The two most-studied compounds, PFOA and PFOS, were phased out of U.S. manufacturing in the 2000s but persist in the environment. Replacement compounds like GenX are now under similar scrutiny.

How PFAS get into water

Three main pathways: industrial discharge, firefighting-foam runoff (especially at military bases and airports), and consumer product decay ending up in landfills and wastewater. From there they leach into groundwater or flow into surface water sources. Because they don't biodegrade, they accumulate. Every part per trillion added stays there.

In South Dakota, the largest known PFAS incidents have been near Ellsworth Air Force Base outside Rapid City, where decades of AFFF firefighting foam training resulted in PFAS contamination of nearby wells. Sioux Falls-area sampling has been ongoing under the EPA's Fifth Unregulated Contaminant Monitoring Rule (UCMR 5), which required all large public water systems to test for 29 PFAS compounds between 2023 and 2025.

What's in Sioux Falls water?

Sioux Falls Water Reclamation regularly publishes its Consumer Confidence Report, and the most recent rounds of UCMR 5 sampling have shown detectable but relatively low levels of PFAS in the municipal supply — below the new EPA maximum contaminant levels for the primary compounds. That's good news. But 'below the limit' and 'zero' are not the same thing, and the EPA's health-based goal for PFOA and PFOS is effectively zero. Any measurable amount is worth thinking about, especially for households with pregnant women, infants, or immunocompromised members.

Private well owners are in a different situation. Wells aren't tested by any public agency. You are your own utility. If you're on a well and haven't tested for PFAS, you don't know what's in it — full stop.

The health picture

The National Academies of Sciences, Engineering, and Medicine, in a 2022 report, linked PFAS exposure to a range of health effects supported by strong or moderate evidence. Those include decreased vaccine response in children, elevated cholesterol, decreased infant birth weight, increased risk of kidney cancer, and thyroid dysfunction. Newer research continues to add associations, particularly around liver enzymes and immune function.

The dose matters, and so does the duration. Nobody is claiming that a single glass of water at 5 parts per trillion will hurt you. The concern is chronic, low-level exposure over decades, combined with PFAS from food packaging, cookware, and household dust. Reducing exposure at the tap is one lever families can actually control.

What actually removes PFAS from water

This is where a lot of homeowners get burned. Most pitcher filters and refrigerator filters make no claim to remove PFAS. Some cheaper 'PFAS' filters remove long-chain PFOA and PFOS but miss short-chain compounds like GenX. The certifications that matter are NSF/ANSI Standard 53 and 58 for PFOA/PFOS reduction, and NSF/ANSI 401 for a broader emerging-contaminant list.

Three technologies are proven to work at the household scale:

• Reverse osmosis (RO): removes 94–99% of both long-chain and short-chain PFAS. Installed under the kitchen sink; provides a dedicated faucet for drinking and cooking. This is what we recommend for most Sioux Falls homes.
• Activated carbon block filters: effective on the well-studied compounds when the carbon volume is sufficient. Point-of-use models certified to NSF 53 or 401 work; the tiny cartridges in most pitchers do not.
• Anion exchange resin: used more in commercial and municipal treatment; expensive and disposable, but very effective for point-of-entry treatment of severely contaminated wells.

Softeners do not remove PFAS. Neither do standard sediment filters, UV lights, or ozone systems. If PFAS is a concern in your household, you need an RO system or a certified carbon block filter — full stop.

What we recommend, step by step

For city water customers: install a quality under-sink reverse osmosis system for drinking and cooking. It handles PFAS along with chlorine byproducts, lead (relevant for older homes with copper plumbing), nitrates, and the taste-and-odor issues that even good municipal water sometimes carries. Total cost installed is typically $650 to $1,200 depending on the model, with $50 to $80 per year in replacement filters.

For well water customers: test first. A comprehensive PFAS well test through a certified lab runs $250 to $400 and is the only way to know your actual exposure. If PFAS are detected above your comfort threshold, an RO system at the kitchen sink is usually the right first step. For heavily contaminated wells, whole-house treatment with granular activated carbon or ion exchange may be warranted — we can coordinate lab testing and design an appropriate system.

What not to do

Don't panic-buy filters based on marketing copy. Anything labeled 'PFAS removal' should have a specific NSF certification listed on the packaging. If it doesn't, treat the claim as unverified. Don't rely on your refrigerator filter for PFAS unless the manufacturer explicitly certifies it. And don't switch entirely to bottled water — a significant fraction of bottled water brands have themselves been found to contain PFAS, and the environmental cost is real.

The long view

PFAS regulations are going to keep tightening. New compounds will get added to the monitored list every UCMR cycle. Municipal water systems across the country are going to spend billions upgrading treatment plants over the next decade, and some of those costs will eventually reach your water bill. Getting ahead of the problem at your own tap — with a proven RO system installed under one sink — is one of the highest-leverage things a household can do for long-term health, at a cost that's genuinely modest compared to the alternatives.

If you want to know what's actually in your water and whether it's worth acting on, we're happy to bring a test to your kitchen table. No pressure, no upsell — just the numbers.