DULUTH – A Pine County township board voted to increase shorefront subdivision lot sizes this week in an attempt to protect lake water quality.

New subdivision lots on lakefront property must be at least 5 acres in size for construction if the property has no public sewer connection, up from 2.5 acres. The change affects the majority of Windemere Township's lake property owners.

The board passed that and other controversial changes proposed by a planning commission after a recent contentious public meeting. The commission did slightly relax some recreational vehicle rules in its final proposal.

The planning commission has said it's trying to curb development to protect the township's extensive body of lakes. Some of them, including Sturgeon Lake, have had issues with sewage runoff for decades, planning commission Chair Paul Horgen said.

"It is absolutely poison," he said, with noncompliant or nonexistent private water systems to blame.

At last week's meeting, several property owners shared concerns about losing lot value, and worried the small township didn't have the capacity to enforce the new regulations.

Horgen said an opportunity to apply for a $15 million federal grant to help pay for a municipal sewer system will go before the town board this month.

Windemere Township is 50 miles southwest of Duluth.