Spurred by concerns over the cost of sprawl, the Metropolitan Council intends to analyze policies that govern the density of growth at the rural fringe of the metro area.

The council’s Community Development Committee on Tuesday asked staff to examine the rules for expanding the area served by regional wastewater treatment pipes. Those boundaries shape and respond to development patterns, in turn impacting the region’s wastewater rates, transportation systems and land consumption.

Met Council policy requires cities’ long-term plans for new development to have at least three housing units per acre — an average across the city — to push the boundaries outward.

But Council Members Cara Letofsky and Steve Elkins asked whether the bar should be higher to ensure efficient use of regional utilities and other infrastructure.

“We people from the core are often told that the core is not subsidizing growth on the rim, but that doesn’t make any sense to me — especially when we see numbers like this,” said Letofsky, referring to the minimum densities needed to expand boundaries. Letofsky represents a Minneapolis-area district.

Requests to extend the boundaries, known as the metropolitan urban service area, have been somewhat rare in recent years — just 11 have been granted since 2010, some because of failing septic systems.

The Community Development Committee has had several meetings about the issue, however, since agreeing to a request from Chaska last fall to accommodate a business park.

Elkins questioned allowing housing development below the required density where the boundaries are expanded.

The Met Council now calculates the density as an average across the city. Met Council spokeswoman Bonnie Kollodge said that gives cities some flexibility “where they can have higher density in some areas and lower density in others.”

Tuesday’s action merely asked staff to look at the issue.

Further change likely would garner reaction from groups that represent metro-area cities and builders.

But Council Member Wendy Wulff, who represents a south-metro district, said cities need time to adjust to any change.

Cities already are submitting the next round of long-term plans, she said, and have made decisions based on the rules currently in place.

“I think we’ve passed the point where we could wave a pen and say go from three units per acre to five because that’s actually a very major change for some communities,” Wulff said.