Sec. 2403. (1) "Allowable service" means a health service delivered in a city, county, district, or part thereof, which is not a required service but which the department determines is eligible for cost reimbursement pursuant to sections 2471 to 2498. (2) "County" includes a unified county unless otherwise specified. (3) "District" means a multi-county or city-county district served by a health department created under section 2415.