Airports say "pet relief areas" enhance customer service. But they're also being nudged by a federal rule that orders airlines to work with airports to install facilities for travelers who have service dogs.
Among airports with dog bathrooms: Atlanta, San Francisco, Los Angeles, Washington Dulles, Washington National, Chicago O'Hare and Phoenix.
The facilities are typically outside, within walking distance of the terminal. The federal rule requires they be kept clean, free of odor, contain a gravel or sand surface and have adequate drainage. Some airports have added synthetic grass, fire hydrants and benches.
About 2 million pets and other animals fly each year in the U.S., according to the Transportation Department. But convenient relief areas weren't required until the department published changes last year to the Air Carrier Access Act, which spells out travel rights for people who have physical disabilities.
Washington Dulles is one of the few airports with indoor facilities within its security zone, in addition to three relief areas outside. Engineers designed them after studying other dog parks. They contain ventilation and wall-mounted water-distribution systems for cleaning.