SALT LAKE CITY — When former Utah Rep. Jason Chaffetz resigned on June 30, he sent state officials scrambling to organize Utah's first congressional special election in 87 years.

Now, counties must cough up hundreds of thousands of dollars in unexpected costs to pay for it.

As counties gear up for the Aug. 15 GOP primary, they're estimating it will cost more than $675,000 to host the special election, particularly in areas that otherwise wouldn't be holding municipal primaries.

Here's the cost breakdown of the 3rd District special election, according to Utah Association of Counties, Utah County and Salt Lake County estimates:

• Utah County: $500,000

• Salt Lake County: $107,000

• Wasatch County: $25,000

• Grand County: $16,000

• San Juan County: $13,000

• Emery County: $6,000

With more than 60 percent of 3rd District voters, Utah County will eat the majority of the cost — which Utah County Clerk/Auditor Bryan Thompson says will be paid for out of the county's "rainy day" fund.

"That's what it's there for," Thompson said of the emergency fund, acknowledging that the special election comes with "significant" unexpected costs.

"But financially we'll be OK," he said. "It's just one of those things that come up."

The financial burden on Utah County, however, has increased from initial estimates of $150,000 to $200,000, Thompson noted, because at least 16 candidates have dropped out of local races, canceling municipal primaries in Lindon, Mapleton and Springville.

"What that means is for every city that cancels, because they're not having a primary, we would pick up the cost," Thompson said.

Utah County is also holding its first ever vote-by-mail election, he said, meaning the county will be paying for printed ballots, return postage, mailers to educate voters of the by-mail election, and about 20 primary polling locations to assist voters who need to vote in person.

"There are just a lot of different things we're doing that we normally wouldn't do in the municipal primary year," Thompson said.

It's an unusual year not only for Utah County. The state hasn't had to hold a special election for a congressional seat since Republican Elmer Leatherwood died in office in December 1929, which led to an election in 1930, according to UtahPolicy.com.

Salt Lake County Clerk Sherrie Swensen said her office is "doing what we can to absorb" the cost of the special election. So far, Swensen said she hasn't had to ask the County Council for a budget adjustment because she had included in her budget a potential countywide primary, as she does every year.

"Still, $107,000 is a concern," she said. "It's a large burden for the taxpayers in Salt Lake County."

Chaffetz did not immediately respond to a request to comment on the costs of the election.

Swensen, Thompson and other local election officials say they plan to seek reimbursement from the state during the next legislative session, according to Lincoln Shurtz, spokesman for the Utah Association of Counties.

"Obviously, especially for Salt Lake and Utah counties, these are significant and unaccounted for costs," Shurtz said, though he added they're "by no means unmanageable."

State Elections Director Mark Thomas said it will ultimately be up to legislators to decide to appropriate funds for reimbursement to the counties, while noting that state officials have agreed to reimburse special election costs in the past.

In 2007, Utah held a special election on the municipal ballot for a statewide referendum, Thomas said. Following that, county clerks requested reimbursements for the cost of the election and they were granted the funds.

Thomas added that election officials estimate that if the District 3 special election hadn't been held during a municipal election, it would have cost much more — between $1.6 million and $2 million.

"That's the reason why Gov. (Gary) Herbert wanted to piggyback the special election on the municipal election, to help minimize those costs," Thomas said.

Three Republicans will be facing off in next month's primary election: Alpine lawyer Tanner Ainge, Provo Mayor John Curtis and former state lawmaker Chris Herrod.

The winner of the Aug. 15 GOP primary will face Democrat Kathie Allen, as well as several minor party candidates, in the November general election.