Families living in the wealthiest attendance area in Chicago Public Schools will soon be cut off from a special perk deemed “unjustifiable” last year by the district’s watchdog: free priority enrollment for coveted seats at a popular Lincoln Park magnet preschool.

Instead, those well-to-do families will have to shell out more than $14,000 for each prized preschool slot at Oscar Mayer Magnet School, 2250 N. Clifton Ave., starting next school year.

That’s because the Chicago Board of Education voted on Wednesday to close the loophole that gave Lincoln Park families first dibs on the free, all-day Montessori preschool seats — which would cost about $30,000 in yearly tuition on the private school market, CPS officials acknowledged Wednesday.

In 2017, Mayer’s staff salaries and benefits cost taxpayers $700,000, while the families living in the attendance zone — with a median income of $177,947, the highest in the district — were able to claim the seats before students from other parts of the city could, according to a scathing report on the program last year by CPS Inspector General Nicholas Schuler.

Only four kids from outside the neighborhood boundary were admitted over a five-year period, Schuler found.

Mayer will become the 12th tuition-based preschool program in CPS.

Students enrolled this year will be grandfathered for free into the second year of the program, but new enrollees will be on the hook for the $14,617 price tag for next school year.

Mayer’s program will remain tuition-based until — or if — former Mayor Rahm Emanuel’s goal of a universal pre-K program is implemented citywide, CPS officials said.

Unlike those other schools that admit children using a citywide lottery, Schuler found that Mayer gave dibs on its 64 available pre-K places last school year to children living in its Lincoln Park boundary, and to its students’ younger siblings, leaving nearly 700 3-year-olds on a waiting list.

That’s because unlike other magnets, which admit children from all over the city, the school never dropped its attendance boundary in 2008 as part of a compromise struck with vocal members of the neighborhood afraid of losing an attendance lottery.

But that compromise also required an annual demographic study to make sure that the school would remain accessible to the many African American families who already traveled to Oscar Mayer after CPS invested in the Montessori program for grades pre-K through five and International Baccalaureate coursework for sixth- through eighth-graders.

About three quarters of Oscar Mayer students enrolled this year are white, in a district where white kids account for just one in 10 students.