The cost of drinkable water in Cottage Grove keeps increasing - but only for 3M Co.

Costs keep racking up for perfluorochemical mitigation projects after the Minnesota Department of Health and Pollution Control Agency lowered levels of recommended PFOS and PFOA levels in drinking water. The city shut down five wells and reduced pumping for three, enacted a watering ban and created a plan to reintroduce water from affected wells at lower PFC levels.

The short-term plan for treatment involves installing eight large-scale granular-activated carbon filters on city well 10 on 95th Street in the next few weeks, a plan estimated to cost $2.2 million, City Engineer Jennifer Levitt said.

PREVIOUSLY: PFC change renews health concerns in Cottage Grove

A similar filtration system will also be added to well 3, to further increase pumping capacity and ease the water ban.

The long-term solution will likely be a water treatment facility, which can cost several million dollars.

Under the settlement agreement and consent order 3M and the MPCA signed in 2007, 3M is required to pay for any remediation costs of issues stemming from their disposal sites.

MPCA program manager Gary Krueger said they consider the issues with Cottage Grove wells to be from 3M. Some Washington County wells near the landfill site may be contaminated by that rather than 3M disposal sites, which the MPCA is responsible for.

"Cottage Grove wells we believe (are) all from the 3M Woodbury site," he said.

Travis Carter, public affairs director with 3M counsel Brewer Attorneys, said 3M has spent more than $100 million on various mitigations efforts.

They footed about $5 million for a water treatment facility plant in Oakdale in 2005, and pay ongoing costs of operation.

VIEWPOINT: Cottage Grove is working to supply water to all

James Kelly, the Minnesota Department of Health's environmental health manager, said he would expect the cost of a Cottage Grove facility to be between that cost of the Oakdale facility and $10 million.

Krueger said their agency will pay costs to the city upfront, but will recover those costs from 3M through an annual reimbursement process.

"We try to be a net neutral as much as possible," he said. "Ultimately we'll try to get all our money back."

3M sent a letter last week to the MDH and Cottage Grove officials contesting total responsibility for PFC levels in city water, saying they could not confirm that all sites were caused by the company and that no other sources could have been involved.

The MDH has since sent 3M a letter confirming the sites of all wells currently tested. Kelly said the MDH's "conclusion all along" has been that 3M is responsible for the PFC levels, and is therefore responsible for mitigation costs under the consent order.

The only possible exception in Cottage Grove is a site near Highway 61 where firefighting efforts may have left traces of PFC contamination, he said.

3M is also responsible for private well mitigation through the MPCA.

Granular-activated carbon filtration systems, which the MPCA will install in homes on affected private wells, cost several hundred dollars. Krueger said contractors will change filters regularly.

"They (homeowners) shouldn't have to worry about any of those costs," he said.

On occasion, Krueger said, other costs including plumbing work in the home, may come up.

"The homeowner may incur some upfront costs, but then the MPCA will reimburse," he said. "We don't want homeowners to have to pay for something they're not responsible for."

Mayor Myron Bailey, in a Facebook post, ensured that citizens the cost will not fall on them.

"We deserve clean water," Bailey said. "We will get clean water. This issue was not caused by Cottage Grove. It should not be paid for by Cottage Grove citizens."