Salt Lake County commissioners officially adopted the county's $220 million 1989 budget Thursday with few changes from the tentative fiscal plan presented to a public hearing last week.

Among the changes, commissioners increased the county assessor's office budget $100,000 to about $6 million and added another $50,000 to the $6.7 million budget for the county attorney's office.Those last-minute budget increases have no tax implications for property owners. Although county tax rates will not be set until next June, the budget projects no increase in property tax rates next year and keeps on track the county's five-year budget plan that projects no tax rate hikes over five years except increases approved by voters.

The Utah Taxpayers Association has estimated the 1989 budget will mean a county tax bill of about $357 for property owners living in the unincorporated county and $222 for city dwellers. Those figures reflect county taxes only. School district, city and any special service levies will add to a homeowner's total property tax bill.

The 1989 budget bottom line is down some $8 million from the tentative figure presented at last week's public hearing. The drop is a result of accounting refinements that eliminated some double budgeting of county internal service funds - accounts that reflect payments for services from one county department to another.

The increase allocated to the assessor's office will fund some staffing of some vacant employee positions, while the attorney's office increase will pay roughly half the cost of operating the county's law library - which the attorney's office takes over next year.

A 4 percent pay-for-performance salary increase for county workers remained unchanged in the adopted budget, as did the $99 million tax revenue projection for 1989.

As expected, the adopted budget shows little or no growth in the level of county services next year. Highway services actually may shrink, an indication of the county's continuing problem of inadequate revenue in the municipal services fund, which pays for services provided to the 285,000 residents of unincorporated Salt Lake County.

The $8 million highway budget absorbed the biggest cut, about $216,000, meaning some needed new equipment cannot be purchased and five vacant employee positions won't be staffed.

Services like snow removal and street repairs probably won't be affected next year, but the county likely will continue to see a revenue shortfall in the municipal services fund of about $900,000 annually, according to the five-year budget plan.

That means eventually a drop in service levels will become noticeable, unless the funding shortfall is addressed, said Commissioner John D. Hiskey.

Another long-term budget issue the commission must tackle in 1989 is how to pay for construction of libraries over the next few years. A planned new library in Sandy, a city-county partnership project, is the focus of that issue.

The city wants to spend $2.5 million, or about twice what the county has been spending on library buildings, and that could throw off track the county's five-year budget plan that allows a new library building every three years on a pay-as-you-go funding basis.