This TreeHugger is a big fan of bidets (and I really like my Toto). Now Scientific American looks at the issue, when a reader asks "Wouldn't a return to installing bidets in bathrooms at home go a long way toward cutting disposable tissue use and saving forests?"
To be pedantic, it is not a return to installing bidets, they have never been popular in America; in fact, they were always a niche market among the rich who did European tours. Harvey Molotch, a New York University professor, studied the bidet and it's trip to America and the New York Times summarized:
Others believe that they never caught on because they took up too much space. But now they have been integrated into toilets and toilet seats, which actually makes a lot more sense than a separate fixture. A bidet is not only is cleaner and healthier, but it has serious environmental benefits. TreeHugger Emeritus Justin Thomas (who wrote our first bidet posts) now edits Metaefficient and tells Scientific American:
The fixture, which was invented by French furniture makers in the early 18th century, was rejected by the English, who regarded French imports as tainted with the hedonism and sensuality of that country. That sentiment, rather than the bidet itself, traveled to America, Professor Molotch said. Later, at the turn of the last century, he said, bidets installed in an upscale Manhattan hotel incited public protest, resulting in their removal. And during World War II, the bidet suffered another blow when American soldiers encountered it in European brothels, perpetuating the idea that bidets were somehow associated with immorality.
Justin Thomas considers bidets to be “a key green technology” because they eliminate the use of toilet paper. According to his analysis, Americans use 36.5 billion rolls of toilet paper every year, representing the pulping of some 15 million trees. Says Thomas: “This also involves 473,587,500,000 gallons of water to produce the paper and 253,000 tons of chlorine for bleaching.” He adds that manufacturing requires about 17.3 terawatts of electricity annually and that significant amounts of energy and materials are used in packaging and in transportation to retail outlets.
That's a lot of water, far more than is actually used by the bidet itself.
There are also the health benefits (summarized here) and the fact that one is far less likely to get any fecal bacteria on their hands. When I designed my bathroom with the bidet/toilet in a separate water closet, readers complained that I wasn't washing my hands before I touched the doorknob. But in fact it is not a problem because the entire operation is hands-free. As they note in Scientific American:
On the public health front, bidet maker BioRelief reports that almost 80 percent of all infectious diseases are passed on by human contact and that only about half of us actually wash our hands after using the facilities—making hands-free bidets a safer alternative all around. “If you don’t have to use your hands at all then there is less chance of passing or coming in contact with a virus,” claims the company.
For the record, I still wash my hands.