Tens of thousands of aging pipes that bring water into Minnesota homes also carry the threat of an invisible neurotoxin: lead.
Prompted by the lead poisoning crisis in Flint, Mich., the state of Minnesota examined the scope of the problem here and what it would cost to fix it. On Thursday, the Minnesota Department of Health provided its estimate: up to $4 billion over two decades. But the benefits, in better health, higher IQs and productivity, could be double that amount, it says.
"We see this report on lead in drinking water as an important next step in that decadeslong public health effort to remove this very significant health threat," Health Commissioner Jan Malcolm said Thursday.
Lead can cause cognitive damage, particularly in children under 6 years old, and harm the nervous system, red blood cells and kidneys. Health officials have continually tightened lead safety standards, according to the department's report, and in 2012 the Centers for Disease Control and Prevention determined that there is no level of safe exposure.
Cities and utilities often treat public water supplies with chemicals, commonly a type of phosphate, to prevent corrosion by creating a protective film inside the pipes. But the report emphasized the need to replace the lead plumbing altogether.
An estimated 100,000 old lead service lines remain across Minnesota. The report says a rough count indicates the majority, 60,000, are in Minneapolis, with another 28,000 in St. Paul and 5,000 in Duluth.
Lead service lines and plumbing fixtures inside the home are the most significant source of lead in public drinking water. A huge challenge in removing them is that the water supplier owns part of the pipe, and the property owner owns the stretch running into the building. The dividing line on ownership is typically somewhere around the curb.
No one knows how many of the estimated 100,000 lead service lines belong to cities vs. private property owners, said Tannie Eshenaur, the Health Department's planning director for drinking water protection. That's why a statewide inventory is such a crucial first step.