If Salt Lake property taxpayers want to retrofit or rebuild the city's schools for earthquake safety, they will have to foot a huge bill - $100 million.

The Salt Lake Board of Education heard Tuesday night that the owner of a $100,000 home would have to pay a $60 per year increase - or five mills - for the next 25 years to cover a $100 million bond.The figures come from a study by district Business Administrator W. Gary Harmer, who reminded the board members last month that they need to worry about how they'll pay for any seismic retrofitting as well as what changes they will make in academic programs and school size.

Harmer, who studied the various size and construction options being considered by the board in deciding the cost, came up with a figure that much higher than numbers that have been floated before. Other cost estimates have ranged from $30 to $80 million.

But even the $100 million isn't set in concrete. The board hasn't looked at the elementary schools, so there wasn't enough information so that Harmer could be very specific, Harmer said.

Harmer said that several bond elections would probably be required because of federal regulations that require the money to be spent within 10 years of the issuance of the bond.

He suggested a more logical plan would be to hold two or three bond elections and phase in the retrofitting and construction. That means it would take 25 years to fix all of the elementary schools by doing about one school a year, he said.

But board President Stephen Boyden pointed out that the district's seismic task force had recommended that all seismic work be done within 20 years.

The elementary schools could be done within 10 years if the some schools were put on double sessions to compensate for the schools undergoing construction or if the entire school district was moved to a year-round schedule, thus increasing each school's enrollment capacity, he said.

Board member Ronald Walker suggested that the district staff check into what state funding California schools received when making its schools more earthquake resistance.

But Harmer and Boyden said they didn't think the receipt of state funds was feasible.

`If our community isn't concerned enough to finance it (seismic retrofitting) with our own money, I don't think the state will pick it up," Boyden said.

Here are the possible phases for construction and bond elections.

Phase I - 6 years

This phase would include the retrofitting and rebuilding of the three high schools plus two elementary schools. The cost would be $36.9 million.

Included in this proposal is the demolition of the 78-year-old classroom wing at East and rebuilding it on the east side of 13th East. Buildings and Grounds Director Steve Harman said a three-story building that would house 2,200 students could be constructed on the east side of the street

But it would probably take configuring the baseball diamond and relocating parking and the tennis courts, along with the technology building, field house and football field, on the west side of 13th East.

This plan would allow East students to attend school in the old building while the new one was under construction. However, the proposal was presented only to show it could be done and is not a recommendation at this point, Harman said.

Phase II - 2 to 3 years

This phase, estimated to cost $25.6 million, would include the retrofitting of the district's five intermediate schools and Horace Mann, which houses the alternative high school.

Phase III - 25 to 28 years

This phase would see the retrofitting or rebuilding of the remaining 25 elementary schools for an estimated $38.7 million.