It is a confusing situation. The law was changed last year to eliminate any further creation of what had been called "impact fees" that cities and counties had begun to establish and to substitute "adequate facilities taxes." The legislation is more constraining, allowing these taxes only in certain counties labeled as "growth counties" and limiting the tax revenue stream to education-related capital expenditure. This legislation requires a super majority. I have printed a good summary of this change below.

From CTAS County Government Handbook- 2006 Supplement (p143)
UT County Technical Assistance Service

Development Taxes and Infrastructure Funding. Adequate Facilities Taxes.
… Before 2006, some counties had levied adequate facilities taxes on the privilege of development under authority granted by private act. In 2006, the General Assembly authorized counties qualifying as “growth counties” to levy a county school facilities tax on residential development. A county may meet the criteria to be a growth county by one of two ways: (1) the county experienced a 20 percent or greater increase in population between the last two federal decennial censuses (or the county experiences that level of growth between any subsequent federal censuses); or (2) the county experienced a 9 percent or greater increase in population over the period from 2000 to 2004 (or over any subsequent four year period). Before the tax may be levied, the county is required to have adopted a capital improvement program. The tax can then be levied by a resolution adopted by a 2/3 vote of the entire membership of the county legislative body at two consecutive, regularly scheduled meetings. The tax may be levied initially at a rate not to exceed $1.00 per square foot. Square footage is determined based on the total heated or air-conditioned residential living space. Once adopted, the rate of the tax cannot be increased for four years. Once the four year period has run, the county legislative body may increase the rate, but by no more than 10 percent. After any increase, the rate is again frozen for a four year period. Public buildings, places of worship, barns and agricultural buildings, replacement buildings for structures damaged by disaster, buildings owned by 501(c)(3) nonprofit corporations, and buildings constructed in an area designated by the federal government as a blighted, distressed, or urban renewal zone are exempt from the tax. All revenue from this tax is turned over to the county trustee for deposit. The revenue is required by law to be used exclusively for funding growth-related capital expenditures for education, including the retirement of bonded indebtedness. The act establishes this law as the exclusive authority for local governments to adopt any new or additional adequate facilities taxes on development. The act prohibits counties from enacting any impact fees or local real estate transfer taxes in the future by either public or private act. The act preserves existing development taxes and impact fees to the extent authorized by any private acts in effect when the act became a law. The act allows a city or county to revise the dedicated use and purpose of the tax levied by a pre-existing tax from public facilities to public school facilities. Counties that levy a development tax or impact fee by private act under prior law may not levy the school facilities tax authorized by this act so long as they are levying and collecting development taxes or impact fees under the authority of the private act. The act includes language that requires the General Assembly, in the 2010 legislative session, to review the provisions of the act to ascertain the effect on and the needs of those counties which did not qualify to levy the tax under the act.