Pumping nutrients into the water supply at the front end would tend to boost the fertilizing potency of sewer water discharged at the other end. The area’s sewage treatment plant had recently spent millions of dollars to reduce the area’s nutrient discharges, which cause excessive algae and weed growths in lakes and streams, and officials didn’t want to offset those gains, Grande said.

But the alternative, replacing lead pipes, would be costly, and the water utility was legally responsible only for the lead pipe that ran from the iron water mains under the streets to the property line of a home or business. The rest of the lead connection leading to the tap was the property owner’s responsibility.

Grande said the DNR insisted on a guarantee that all the lead would be replaced, so the city passed an ordinance requiring residents in older properties to replace their pipes, setting off a backlash over costs that would run to thousands of dollars for each homeowner.

“We had to figure out a way, particularly for low-income people, how they were going to be able to afford that,” said Sue Bauman, who was mayor from 1997 to 2003.