More Japanese households now have a washing toilet seat than a car. The idea came from America, the engineering from Japan, and the rest of the world is still catching up. How it happened, and what the buttons do.
Japan’s Toilet Technology
More common than a car
In March 2026, 82.5% of Japanese households with two or more people had a warm-water washing toilet seat. That is more than had a car (76.2%) or a computer (74.7%), and on average there are 117 seats for every 100 of those households. The Cabinet Office tracks them alongside air conditioners and televisions, as ordinary household equipment.
The idea was imported. Japan’s restroom industry dates the washing seat’s arrival to 1964, when an American design, the Wash Air Seat, reached the country. It had problems: the water could come out at the wrong temperature, and the spray did not reliably hit its target. TOTO’s own history describes both complaints.
Japanese makers spent the next two decades fixing them. In 1967 the company now called INAX introduced the Sanitarina 61, a toilet with warm-water washing and drying, and in 1976 it sold the system as a seat that fits an existing toilet. TOTO began work on its own model in 1978, measuring more than 300 volunteers to work out where the spray should go. It launched the WASHLET in June 1980. The brand name stuck, but INAX had been selling washing toilets for years.
Sources for this section ↓Across the Pacific
Why the American version stalled
Brooklyn inventor Arnold Cohen developed a washing-and-drying seat in the 1960s to help his father. Selling it was the hard part. In a 2007 interview with the Miami New Times, he recalled newspaper ads, trade shows and buyers who did not see the point. In 1964 a Japanese trading company took an interest and adapted the device for Japan.
Cohen’s American Bidet company never came close to Japanese household numbers. It did survive: in 2007 he was still making seats in Florida and selling them online, and he estimated his lifetime sales at a few hundred thousand at most. Kohler introduced its C3 washing seat in 2006 and, in 2011, the Numi, with a bidet, heated seat, foot warmer, automatic lid and built-in music.
The gap is in ordinary homes. In a 2022 YouGov survey, 6% of US adults said they already had a bidet at home. Interest is growing among people who renovate: in Houzz’s 2025 study, 21% of homeowners adding or upgrading a toilet chose a bidet seat. Those renovators are not a sample of all American homes, but they show where interest is growing.
Sources for this section ↓A closer look
Using one
The TOTO remote in the photo puts the main choices along the top: stop, rear wash, a gentler rear wash and front wash. Below are water pressure and nozzle position, which move the spray instead of making you move. Smaller buttons set the seat and water temperature separately, clean the nozzle, deodorize and save power. Stop is the button to find first.
Owning one is not the same as using it. In an industry survey of 4,700 people with washing seats at home, 79% said they use them at least some of the time; those who do not mostly said they had never got used to it or did not know what the functions do. In January 2026 the Japan Restroom Industry Association responded with a rap video starring actor Yōichi Nukumizu, whose surname means “warm water” and who was born in 1964, the year the washing seat reached Japan.
Visitors can find the technology in public, too. Between 2020 and 2023 Shibuya opened 17 public toilets designed by 16 architects and designers, including Tadao Ando, Shigeru Ban and Kengo Kuma, all accessible and fitted with washing seats. Wim Wenders’ 2023 film Perfect Days follows a man who cleans them; Kōji Yakusho won Best Actor at Cannes for the role.
