COTTAGE GROVE - About 43 percent of private east metro wells tested in 2018 led to well advisories, according to a Minnesota Pollution Control Agency memo.

In 2018, 351 well advisories were issued from a total 809 residential wells sampled through coordinated efforts by MPCA and the Minnesota Department of Health.

Pollution control official Gary Krueger said the large increase in well advisories can be attributed to the Minnesota Department of Health lowering what it considers an acceptable amount of the contaminant PFAS in drinking water. The adjustment was made in May 2017 after the department looked at potential health impacts of the contaminant, Krueger said.

The number of residential wells sampled in 2018 accounts for nearly 30 percent of those tested for PFAS compounds since 2003 when such sampling began.

Most of these samplings were carried out as part of routine testing as a result of the state’s lowered criteria. Washington County residents could also request to have residential wells tested for PFAS, though many requests overlapped with planned samplings in 2018.

A similar number of residential well samplings are planned for 2019, Krueger said.

Most of the wells sampled in 2018 were tested for the first time. Nearly half of these were located in West Lakeland Township, between Lake Elmo and Lakeland.

When a resident is informed that an advisory has been issued for their private well, pollution control offers to provide bottled water until the state can install a granular activated carbon filter or, in some cases, until the residence can be connected to city water.

Krueger said areas that have been monitored historically, including Cottage Grove, Lake Elmo and Woodbury, show “fairly constant” PFAS levels, and some even show a decline. Some areas in the east metro show slightly increasing levels, though these can be explained by geological features that impact sampling, Krueger said.

A lawsuit brought against 3M Co. settled in February 2018 for $850 million alleged the company dumped PFAS compounds, also referred to as PFCs, into east metro drinking water and groundwater for years.

By the numbers


  • Wells sampled in 2018: 79
  • Advisories issued in 2018: 23


Cottage Grove

  • Wells sampled in 2018: 132
  • Advisories issued in 2018: 25



  • Wells sampled in 2018: 2
  • Advisories issued in 2018: 1


  • Wells sampled in 2018: 0
  • Advisories issued in 2018: 0

St. Paul Park

  • Wells sampled in 2018: 11
  • Advisories issued in 2018: 7



  • Wells sampled in 2018: 28
  • Advisories issued in 2018: 0