(a) A development impact fee shall not exceed a proportionate share of the cost of system improvements, as defined in this chapter.

(b) Development impact fees shall be calculated and imposed on the basis of service areas.

(c) Development impact fees shall be calculated on the basis of levels of service for public facilities that are adopted in the municipal or county comprehensive plan that are applicable to existing development as well as the new growth and development.

(d) A municipal or county development impact fee ordinance shall provide that development impact fees shall be collected not earlier in the development process than the issuance of a building permit authorizing construction of a building or structure; provided, however, that development impact fees for public facilities described in subparagraph (D) of paragraph (16) of Code Section 36-71-2 may be collected at the time of a development approval that authorizes site construction or improvement which requires public facilities described in subparagraph (D) of paragraph (16) of Code Section 36-71-2.

(e) A municipal or county development impact fee ordinance shall include a schedule of impact fees specifying the development impact fee for various land uses per unit of development on a service area by service area basis. The ordinance shall provide that a developer shall have the right to elect to pay a project's proportionate share of system improvement costs by payment of development impact fees according to the fee schedule as full and complete payment of the development project's proportionate share of system improvement costs.

(f) A municipal or county development impact fee ordinance shall be adopted in accordance with the procedural requirements of Code Section 36-71-6.

(g) A municipal or county development impact fee ordinance shall include a provision permitting individual assessments of development impact fees at the option of applicants for development approval under guidelines established in the ordinance.

(h) A municipal or county development impact fee ordinance shall provide for a process whereby a developer may receive a certification of the development impact fee schedule or individual assessment for a particular project, which shall establish the development impact fee for a period of 180 days from the date of certification.

(i) A municipal or county development impact fee ordinance shall include a provision for credits in accordance with the requirements of Code Section 36-71-7.

(j) A municipal or county development impact fee ordinance shall include a provision prohibiting the expenditure of development impact fees except in accordance with the requirements of Code Section 36-71-8.

(k) A municipal or county development impact fee ordinance may provide for the imposition of a development impact fee for system improvement costs previously incurred by a municipality or county to the extent that new growth and development will be served by the previously constructed system improvements.

(l) A municipal or county development impact fee ordinance may exempt all or part of particular development projects from development impact fees if:

(1) Such projects are determined to create extraordinary economic development and employment growth or affordable housing;

(2) The public policy which supports the exemption is contained in the municipality's or county's comprehensive plan; and

(3) The exempt development's proportionate share of the system improvement is funded through a revenue source other than development impact fees.

(m) A municipal or county development impact fee ordinance shall provide that development impact fees shall only be spent for the category of system improvements for which the fees were collected and in the service area in which the project for which the fees were paid is located.

(n) A municipal or county development impact fee ordinance shall provide that, in the event a building permit is abandoned, credit shall be given for the present value of the development impact fee against future development impact fees for the same parcel of land.

(o) A municipal or county development impact fee ordinance shall provide for a refund of development impact fees in accordance with the requirements of Code Section 36-71-9.

(p) A municipal or county development impact fee ordinance shall provide for appeals from administrative determinations regarding development impact fees in accordance with the requirements of Code Section 36-71-10.

(q) Development impact fees shall be based on actual system improvement costs or reasonable estimates of such costs.

(r) Development impact fees shall be calculated on a basis which is net of credits for the present value of revenues that will be generated by new growth and development based on historical funding patterns and that are anticipated to be available to pay for system improvements, including taxes, assessments, user fees, and intergovernmental transfers.