A court-ordered mediation session between Cobb County government and the Cobb County School District ended Friday, July 31, without agreement, leaving a lawsuit over millions in tax-collection fees headed for trial and putting pressure on a district budget that funds Walton, Pope, Lassiter and Wheeler high schools.

Cobb County announced the breakdown Tuesday, Aug. 4. The dispute centers on administrative fees the county withholds from school property tax revenue before passing it to the district. The school district says this fiscal year's fees are projected to top $13 million, enough to cover roughly 130 teachers' salaries and benefits.

The district filed suit in June against the Cobb County Board of Commissioners and Tax Commissioner Carla Jackson, calling the charges "exorbitant and unlawful." According to CBS News Atlanta, the district alleges it has paid more than $130 million in such fees since 2011.

Under Georgia law, counties may withhold up to 2.5% of school tax collections as a commission. Cobb County says its actual rate has been 1.6% for decades, according to WSB Radio. The district argues that rate has been unlawful since 2011 and should be zero. The county counters that without local legislation setting a lower rate, the lawful commission is actually the full 2.5%.

The county stated that the district's claim the 1.6% rate was unlawful has not been raised in the last fifteen years.

John Floresta, the district's chief strategy and accountability officer, issued a statement following the failed mediation: "Whether it's $13 million or $20 million, and whether it's called a tax on top of taxes or a 'fee,' taking even one dollar that taxpayers intended for students doesn't work for our Board or our Superintendent."

Cobb County said it mediated in good faith but that a resolution was not reached, adding that its responsibility is to protect taxpayers and maintain county services.

Board of Education Vice Chair David Chastain framed the stakes when the lawsuit was filed in June, saying the commission amounts to a tax increase disguised as administrative fees and calling for smaller class sizes rather than more fees.

As we reported July 24, the school board held its millage rate at 18.7 mills for the current year. Any reduction in revenue from this fee dispute would compound already tight per-pupil spending. Floresta noted in his statement that Cobb teachers serve students at one of the lowest per-pupil costs in the metro area.

With mediation exhausted, the lawsuit moves through Cobb County courts. No next hearing date has been announced.