Eagan's oldest water tower, which has been empty for years, will be torn down and replaced with a communications antenna, the City Council informally agreed this month, ending speculation that the structure could be rehabbed and preserved as a landmark.

The Sperry water tower, off Pilot Knob Road north of the Eagan Community Center campus, needs as much as $600,000 worth of repairs in order to remain safely standing, the city says. But simply tearing it down would mean the loss of about $150,000 annually in payments from telecommunications companies that have antennae on top of the tower.

Of 273 people who responded to an online survey offered in January and February, about 75 percent said saving the water tower as a landmark was of little or no importance, city spokesman Tom Garrison told the council at a workshop on Feb. 11.

To preserve cellphone coverage — as well as key communications equipment used by public safety personnel, which also sits atop the tower — the city would need to erect a new structure. The cost of demolishing the tower would be $40,000 to $60,000, and a new antennae tower could run $100,000 to $300,000, the city says.

"There's really clearly one option here that makes sense, and that's taking down the existing structure and building a purpose-built communications tower," said City Council Member Paul Bakken.

The council instructed Public Works Director Russ Matthys to proceed with more detailed cost estimates and feasibility studies for replacing the tower.

Mayor Mike Maguire said that he'd like to make the replacement structure as attractive as possible, as many of the survey respondents had suggested, but that keeping the cost down and maximizing its capacity to hold more equipment in the future would be crucial.

Ideas for preserving the water tower, built in 1967, ranged from keeping it in its current state to more fanciful proposals such as turning it into a public art piece or even using it for housing.

"I think it would be a hoot to live in a disused water tower," one survey respondent said. "Especially if you could cut windows into the perimeter, and have a 360 degree view of the river valley from 160 feet up."

At the same time, "We certainly did hear from those taxpayers who said 'Whatever was least expensive,' " Garrison said.

Council members said they'd favor talking to local arts and historical groups about whether a piece of the old tower could be saved and reused in some way.