Officials for the Hartsfield-Jackson Atlanta International Airport recently revealed that its seven new Service Animal Relief Areas, which were installed last year, cost a total of $3.9 million.

The airport installed the seven dog bathrooms, one in each concourse, last summer, but the cost to construct them was made public only this week, Fox 5 Atlanta reports.

Airport administrators credited the high price tag to the complexities of building inside a 24-hour facility, which restricts construction to the overnight hours. Additionally, they said existing facilities had to be torn down in order to make room for the new dog bathrooms.

The Federal Department of Transportation mandates large airports have Service Animal Relief Areas.

“In order for ATL to be in compliance with federal ADA (Americans with Disabilities Act) standards, these relief areas had to be built,” a spokesperson for the airport told Fox News.

“The total cost for building the seven relief areas was absorbed through airport funding, not taxpayer dollars, in the amount of $3.9 million, which is reimbursable through PFCs (Passenger Facility Charges).”