The City of Cedarburg thought they had done everything right. Within weeks after the pond was completed, neighbors began calling with complaints that the pond was ugly and smelly. Virtually the entire surface of the pond was covered with a native algae called waternet.
City officials couldn t figure out why.
When DNR and city staff began looking for illicit sources of wastewater, all they could find was a clean-looking discharge of cooling water from a metal fabricator. Further tests supported the industry s claim that the phosphate came into their plant from the city s tap water. Cedarburg, like many other cities, has problems meeting drinking water standards due to copper and lead leached out of old pipes and solder. The least expensive solution is to add a phosphate compound at the filtration plant to coat the pipes, make the water less acid and thereby reduce metal leaching. In our efforts to protect public health, we have started adding the very chemical to the water that we banned from detergents to prevent lake eutrophication.