Harford County has appealed a Circuit Court judge's decision upholding a 1969 contract between the county and Bel Air that gave the town 99 years of free waste disposal at county landfills in return for the land where the county detention center stands.
The county also has given the town until June 30 to accept a settlement, a county spokesman said.
Judge Maurice W. Baldwin heard testimony on the validity of the contract in the six-day trial, which ended May 30.
Judge Baldwin said he would not overrule a 1982 decision by visiting Baltimore County Circuit Judge John Fader that ruled the 1969 contract was valid.
The county contends Bel Air owes $35 for each ton of trash it dumps and has billed the town for more than $350,000, including interest, since it began collecting a fee from trash haulers in 1992.
On Friday, County Executive Eileen M. Rehrmann sent a letter to town officials that said the county believes it has "a strong basis for success on appeal."
The letter also said the county would offer town officials a "permanent 15 percent reduction" in the fee, wipe out all past billings and interest and not begin charging for future waste disposal costs until July 1.
Mrs. Rehrmann said the settlement offer will be withdrawn if not accepted by June 30.
No Bel Air commissioner was at town hall to receive the county executive's letter, a spokeswoman at town hall said.
Bel Air attorney Charles B. Keenan Jr., who has represented the town in the litigation, said Friday he had just received the letter.
"All of the commissioners will have to see the letter, study it and discuss it before making any official response," Mr. Keenan said.