More students and more calls to downtown are taking a toll on the local ambulance service, requiring the county to chip in more money to support the service.

"The population is growing dramatically," said Johnson County Supervisor Janelle Rettig. "There is no single blame for that increased call volume of ambulances, but there is a contributing factor that there are more students here."

Steve Spenler, the director of the Johnson County Ambulance Service, said the number of ambulance calls has increased by 3 percent this year, adding to the 25 percent increase in ambulance calls in the past five years.

County officials recently changed the software they use to track ambulance calls are so data on those calls are sparse. For instance, officials can’t say how many calls are coming from students.

However, Spenler said, the busiest time of the week for ambulances is on the weekends, and calls have increased in downtown —even as city officials tout the positive effect of 21-ordinance.

"Our calls into downtown Iowa City since 2009 took a bit of a decrease by 2010, and I think they are back up," Spenler said.

Given these numbers, county officials worry more calls by students and the public could be costing the county more.

Funding from the county to the Ambulance Service is just over $795,000 —almost $200,000 more than last year.

Spenler said the Ambulance Service receives $75,000 from the UI Children’s Hospital and $67,000 from the university to provide service for UI athletic events, but the county is not contracted to provide on-call service for university students on a day-to-day basis.

"We’re having to tax more to help subsidize," said Supervisor Terrence Neuzil. "And any time people see their taxes increase, we need to find a way to justify that expense."

Supervisors say they’re pleased with the Ambulance Service’s record — including better arrival times, a new ambulance, and outreach projects — but those things come with extra costs.

Costs that will, Neuzil said, continue to increase.

"In general, when you see a 25 percent increase in the last five years for a service, it clearly indicates that the demand is going to increase," he said.

"It’s a double-edged sword — it puts more of a toll on our county budget when our student population increases …" he said. "On the one hand, it’s great to have the university; on the other hand, it’s expensive to have the university."