Delaware's population growth has been virtually nonstop since Dean Stelzer became the city's finance director in August 1990.

The population was about 18,000 in 1990, Stelzer said. City leaders said Delaware now has more than 42,000 residents.

As a result, Stelzer said, "The dynamic of the community has changed a lot. In the early '90s, many people in Delaware had lived in the city their whole life."

Stelzer will retire from his city job Tuesday, Jan. 21. The Delaware County Sheriff's Office said Stelzer will start a new job there April 1.

"We'll be combining the previously vacated finance manager and director of administration (positions) with the hire of Stelzer," said Sheriff Russell Martin. "Dean will continue to help us manage the stewardship of our budget while helping us plan for the future."

In 1990, Stelzer said, the city saw growth coming.

"I knew when I came here that Delaware would grow, whether it wanted to or not," he said.

Since then, he said, a guiding principle for city officials and Delaware City Council members has been, "Let's try to plan for growth in a way that doesn't change the community."

A goal was to avoid suburban sprawl, he said -- and he thinks the city did a good job.

"It's been interesting to observe that," he said.

But one challenge, Stelzer said, was to find a way to pay for increasing services needed by a growing population without raising taxes.

The answer was impact fees, or charges placed on new construction that sets aside money for capital costs related to services, he said.

In Delaware, he said, the average new house costs at least $300,000. Such a house may incur one-time fees of $5,385 for sanitary sewer, $5,650 for water treatment and $162 for police services.

Other impact fees set aside money for parks, fire services and municipal services, Stelzer said.

The rates are based on an analysis of growth's impact on city facilities, he said, and the money is used only for the physical expansion of facilities. Any other expenditure, such as repairing existing facilities, would require a tax, he said.

Impact fees aren't common in Ohio, Stelzer said, because only a few areas have enough growth to warrant them. As a result, the General Assembly never passed legislation regulating the fees, he said.

Instead, Stelzer said, a couple of court cases in the early 1990s determined the fees and their expenditures weren't an illegal tax.

"Everybody was watching" the cases, he said.

The city conducted a lot of research and analysis before enacting impact fees around 2001, Stelzer said.

One step was to determine the effect a single residence would have on city services, and the fees that were enacted are lower than those estimates, he said.

The fees affect only new construction. Work on an existing house, by comparison, doesn't increase the city's population, he said. A different fee schedule also exists for retail buildings, he said.

One example of impact-fee expenditures was the expansion of the city's Justice Center, 70 N. Union St., he said.

An event that affected every Ohio municipality financially was the Great Recession that erupted in late 2007.

"When the recession hit, Delaware had it easier than a struggling area where people already were moving out," Stelzer said.

Delaware also benefited, he said, because, "We always manage our resources. We don't overextend ourselves. We don't commit to services we can't sustain. ... We have a Plan B and Plan C if things don't pan out as expected."

The city avoided staff cuts by not replacing some employees who resigned, he said.

"I don't think anybody noticed any change in the level of services," he said.

Delaware City Manager Tom Homan said he was grateful to have had Stelzer's "expertise and friendship" for so long.

"Our city has a very healthy financial profile, and that is because of Dean's prudent fiscal management," Homan said.

Martin said the two combined posts Stelzer will fill have been vacant for more than a year.

Stelzer said he had helped Martin interview candidates for the vacancies before Martin asked him if he would be interested.

Stelzer will earn $97,500 annually, Martin said.

Delaware spokesman Lee Yoakum said Stelzer earns $135,844 annually with the city.

Justin Nahvi will step in as the new finance director, earning $124,000 annually.