When the Lead and Copper Rule was first issued in 1991, it put federal limits on the acceptable amount of these metals found in drinking water. Cities started testing their water. Researchers experimented with chemicals that could inhibit the corrosion of pipes — the main source of contamination. But for some cities, like Madison, Wis., that simply wasn’t enough. "[The Lead and Copper Rule] has a fundamental flaw, and that is: it's over-simplistic. It doesn't acknowledge the multiple factors by which lead and copper leave piping materials and get into the drinking water," says Abigail Cantor, the president of Process Research Solutions , a consulting firm based in Madison that specializes in drinking water quality. After extensive testing, Cantor found that Madison’s water could not be fully controlled without removing its lead pipes. So in 2001, the city took an uncommon step: it removed the pipes. Nearly two decades later, Milwaukee still has lead pipes. But, why? Cantor says the