Based on our measurements, Bidets use about 1/6 of a gallon of water for each trip to the bathroom.

Toilet paper is actually made using a fair amount of water. According to our estimates, it takes about 6 gallons of water to make one roll of toilet paper. 

So, which option is better? If you break water use down by each trip to the bathroom, bidets use about the same amount of water or less and they don’t waste trees. So, from an environmental and hygiene perspective, a bidet is the better choice. And if you’re low on toilet paper anyway, it might be worth it! 

Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet and break them down into small questions with unexpected answers. I’m Megan Hall. 

Megan Hall: Today, we’re going to talk about something personal: our bathroom habits. Toilet paper is flying off the shelves in this pandemic.

So, some people are turning to bidets for their bathroom needs. 

This made us wonder, which option is less wasteful? 

Megan Hall: We had Fatima Husain from our Possibly Team look into this. Welcome, Fatima! 

Fatima Husain: Hi, Megan!

Megan Hall: So, my guess is it’s a toss-up between using a lot of trees to make toilet paper and using a lot of water to run a bidet. 

Fatima Husain: Actually, it’s not that simple. The process for making toilet paper involves a lot of trees AND a fair amount of water. 

Megan Hall: In what way?

Fatima Husain: Before trees can become that fluffy paper that’s wrapped into neat little rolls, they have to be pressure cooked, treated with chemicals and turned into a soggy pulp.

Megan Hall: So, how much water does goes into making one roll of toilet paper?

Fatima Husain: I couldn’t find any studies on this, but according to a tool made by the Environmental Paper Network, approximately 6 gallons of water are used to make one roll.

Megan Hall: Wow! What about toilet paper that comes from recycled paper or newspapers? Is it any better?  

Fatima Husain: Yes! A roll made from 100% recycled materials uses half as much water. 

Megan Hall: So, what about Bidets? How do they work?

Fatima Husain: If you haven’t used a bidet before, it looks pretty much like a toilet bowl with a tap on one side that gives you a rinse after you go. Bidets or some version of them are already used a lot in Europe, Latin America and some parts of Asia. 

Actually, our Possibly reporter Isha Chawla is an expert on this topic. She’s at home in India right now, where jet sprays and bidets are common. I called her up for an explanation of how these contraptions work. 

Isha Chawla: A jet spray is quite like the kitchen sprays that some kitchens in the US have. And in that if you were to install it in your bathroom, it takes up much less space than having a bidet and it's also less expensive.

Fatima Husain: She says spraying yourself with water is easy, and probably more hygenic: 

Isha Chawla: If you ate food on a plate, you wouldn't just wipe the plate with tissue. You’d probably wash the plate.

Megan Hall: But these methods have to use a lot of water — how do they compare to the up to 6 gallons that are used to make a roll of toilet paper? 

Fatima Husain: To find out, Isha timed how long the spray runs when she uses it normally, and then separately sprayed water for the same amount of time into a small container.

She says that it came to about a sixth of a gallon of water.

Megan Hall: Do the math for me. Is that more or less water than a trip to the bathroom using toilet paper?

Fatima Husain: Again, it depends on a few factors, including how many sheets and the ply you use. But, based on our calculations, it takes at least the same amount of water or more to make the toilet paper you use for each trip. 

Megan Hall: So bidets use about the same amount of water and they don’t waste trees? Why doesn’t everyone use them instead?

Fatima Husain: That’s what Isha — and her friends — think! When she moved to the US for college, she got a special farewell present. 

Isha Chawla: one of my close friends got me a portable jet spray. Which is hilarious, because she was just like, this is the one thing that I know you probably miss most. 

Megan Hall: Does that mean I should run to my computer and order a bidet?

Fatima Husain: Well, from an environmental and hygiene perspective, a bidet is the better choice. And if you’re low on toilet paper anyway, it might be worth it! 

Megan Hall: Great, thanks Fatima! And thanks to Isha Chawla who also helped with today’s episode.

That’s it for today. For more information, or to ask a question about the way you recycle, use energy, or make any other choice that affects the planet, ask about it here. Or, subscribe to Possibly wherever you get your podcasts. 

Possibly is a co-production of the Institute at Brown for Environment and Society and the Public’s Radio. 

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Where we got our numbers...

I weighed a roll of charmin toilet paper. It is 5.1 oz. Then I weighed the cardboard tube inside it. It is 0.3 oz. So, there's about 4.8 oz per roll of toilet paper, which is about 0.3 pounds of toilet paper. I input that number into this calculator: https://c.environmentalpaper.org to calculate water use per roll for 100% virgin fiber toilet paper, 50%, and 0%. Screenshot at end. 

Charmin rolls have 284 sheets/roll. RISI, an independent market research firm, notes that women use 7 sheets each time they're in a public restroom. So, I know we're not talking exact equivalents in terms of TP, but this is the only way I can stick to citable-ish numbers. 

284 sheets/roll divided by 7 sheets/trip means that you can make 40.57 trips per roll (I think this is a bit high — it’s probably less so that makes our calculation a lower bound). 

6.1 gallons / roll over 40.57 trips/roll comes to approximately 0.15 gallons/trip.

New Sources:

https://handyfinch.com/minimalism-zero-waste/zero-waste-bathroom/plastic-free-toilet-paper

https://handyfinch.com/wp-content/uploads/2019/09/Environmental-Paper-Report.pdf

https://c.environmentalpaper.org