PFAS Filtration: How Grassroots Advocates Changed Hempstead
A grandmother's door-to-door campaign helped secure a $60M water plant upgrade in Hempstead, spotlighting PFAS contamination on Long Island.
Mary Purdie spent her weekends going door to door through Hempstead, clipboard in hand, asking her neighbors a simple question: What is in our water?
The 72-year-old grandmother collected 500 signatures calling on local officials to address toxic chemicals in the village’s drinking water. Her motivation was straightforward. “My thing is: How come so many people in Hempstead are dying from cancer?” she told NBC 4 New York. “Like, wait a minute, something is wrong in this picture.”
This past January, her persistence paid off in a significant way. Officials announced a $60 million upgrade of the village’s water plant, with Congresswoman Laura Gillen pointing directly at residents like Purdie as the reason the project moved forward. “Part of the reason we are here today is the grassroots activism of people like Miss Purdie,” Gillen said at the announcement.
The chemical at the center of this fight is PFAS, short for per- and polyfluorinated alkyl substances. Researchers call them “forever chemicals” because they don’t break down naturally in the environment or in the human body. The U.S. Geological Survey estimates that at least 45% of the nation’s tap water contains one or more types of PFAS. On Long Island, that number is not a distant statistic. It is a local reality.
PFAS became so pervasive because they were genuinely useful. Starting a few decades ago, manufacturers adopted them widely to make products resistant to heat, water, and stains. The chemicals ended up in nonstick cookware, waterproof clothing, food packaging like pizza boxes and microwave popcorn bags, cosmetics, and firefighting foams. The convenience came with a cost that took years to understand. PFAS contamination has spread into soil and water supplies across the country, and the USGS notes there are more than 12,000 types of PFAS, not all of which current tests can even detect.
The response on Long Island has accelerated. In Glen Cove last month, the City Council approved a $776,000 project to improve the filtration system at its water facility on Seaman Road, with additional work at other city facilities either underway or planned at a cost of millions more. The upgrades involve granulated activated carbon filter systems, which are specifically designed to capture and treat PFAS before water reaches the tap.
Perhaps the most significant regional achievement came from Suffolk County. The Suffolk County Water Authority announced that all water flowing to its 1.2 million customers is now in full compliance with federal drinking water standards for PFAS, reaching that benchmark six years ahead of the EPA’s 2031 deadline of four parts per trillion. “Given the extent of PFAS detections across Long Island and the size of our system, this is a historic achievement,” said SCWA Chairman Charles Lefkowitz, adding that the authority is working to “stay ahead of emerging threats to public health.”
That kind of early action matters because the regulatory and scientific picture around PFAS keeps evolving. New types of these chemicals are still being identified, and health researchers are still working to understand the full range of risks they carry. The forever-chemical problem didn’t arrive overnight, and resolving it won’t happen overnight either.
What has changed is the momentum. Across Nassau and Suffolk counties, water authorities and municipal governments are investing heavily in filtration infrastructure. The dollars involved are significant: Hempstead’s $60 million project, Glen Cove’s multi-project commitment, Suffolk’s system-wide compliance effort. Behind each of those line items is a recognition that the tap water Long Islanders use every day requires ongoing attention and serious investment.
And behind at least one of those projects is a grandmother from Hempstead who knocked on strangers’ doors and refused to stop asking questions. Purdie’s approach was not complicated. She saw a problem in her community, she documented it, and she brought it to the people who had the power to act.
Local advocates and public health officials alike are watching what comes next, both in terms of new PFAS research and new filtration standards. Purdie’s story offers something useful for that longer effort: a reminder that the push for cleaner water has always been most effective when it starts close to home.