How Bidets Save Water (For You and the Environment)

How Do Bidets Save Water

Today’s article looks at how bidets can save on water both for the user and the environment. One of the most common questions I get asked is, do bidets save water? It usually comes from folks interested in saving resources for environmental and sustainability concerns.

Bidets do save water overall. They use a negligible amount of water per cleaning session (about 0.05-0.1 gallons) while reducing or replacing the need for toilet paper, which uses 37 gallons of water to produce a single roll. Users can expect to save water by flushing less often.

It’s always been interesting to me that this is a common question. Bidets clean with water instead of paper so it wasn’t obvious to me that the water-saving benefits of bidets would be widely known. 

Anyway, let’s dive in.

How Do Bidets Save Water? 

Society-wide, bidets save water by reducing the demand for toilet paper, a product whose production requires trillions of gallons of water annually. Bidets save consumers water by reducing the need for flushing. I.e., multiple flushes are no longer needed to prevent clogged toilets.

For those who are new to the subject, here are some of the labels we’ll be using: 

All bidets use far less water than other appliances, but electric bidets are the most efficient. Attachments are pretty good too.

How Bidets Save Water and Help the Environment 

Bidets save water at the consumer level and we’ll get more into that further down in the article. But they really shine when it comes to how much water they save at the level of the environment.

Bidets save water by reducing the demand for toilet paper. Because a single roll of TP takes 37 gallons to produce, widescale bidet use has the potential to save trillions of gallons of water per year worldwide—about 259 billion in the US alone. 

How did I get that massive number? 

  • As mentioned, it takes 37 gallons of water to produce one roll of toilet paper. This is according to Scientific American (1). 
  • Estimates vary wildly, but it’s thought that Americans use between 7 and 36.5 billion rolls of toilet paper per year (1,2). 
  • If we take the “low” number, that’s 7 billion x 37 gallons which equals 259 billion gallons of water used annually–or saved annually if we all started using bidets. And that’s just in the USA. It’s more likely in the trillions of gallons (see the below stats).

Here are some other fun stats that can help explain the phenomenon. They’re taken from different sources, so the numbers shouldn’t be expected to add up perfectly. 

Fun stats: 

  • The conservative number of 7 billion comes from the fact that annually Americans in the USA use an average of 23.6 rolls per capita per year (2). With a population of over 320 million, this would come to at least 7 billion rolls.  
  • But, Scientific American estimates that Americans use 36.5 billion rolls of TP annually (1). With 37 gallons of water needed to make only one roll, 1.3505e+12 gallons are needed to meet the annual TP demand in America alone. They go on to say that widescale adoption of the bidet could save 15 million trees per year. 
  • I’ve read elsewhere that each day some 83 million rolls of TP are made using 27 thousand trees. If you crunch the numbers, 37 x 83,000,000 x 365 = 1.120915e+12 gallons of water used annually in toilet paper production.
  • On average, a tree weighing 1000 lbs. produces 810 rolls of toilet paper. It depends on the size of the roll. Rolls can contain as few as 200 squares. But the most common number of sheets per roll is 500 and 1000 for 1-ply and 2-ply, respectively. Jumbo rolls can reach up to 2000 sheets. 
  • Each lifetime TP user in the US can expect to use 348 trees worth of toilet paper.
  • Three hundred and forty-eight trees per person? That’s right. It turns out folks tend to use 57 squares of TP per day each (3). That comes to 228 squares per four-person household. As we’ll get into later, it’s not supposed to take that much.

How Bidets Help Consumers Save Water 

Making the switch to a bidet doesn’t always result in savings for the consumer. It depends on the type of bidet and the water conservation habits of the user. 

Bidets help consumers save water only when the person ends up flushing less. Net water savings are helped when the bidet is both water-efficient (e.g., aerated nozzles and moderate spray volumes), and effective enough to give a thorough clean in a single spray session (typically a minute or less).

After ditching TP, folks invariably end up flushing less whether they realize it or not.

No More Flushing Paper

The water used by flushing the toilet throughout the day can add up big time. 

Since the EPA Act of 1992, water conservation regulations call for newly-built toilets to use no more than 1.6 gallons per flush (GPF) (4). In the olden days, the limit was a lot higher and many toilets still in use today use 3.5-5 gallons per flush. 

According to the 2016 Residential End Uses of Water Study, the average consumer will flush the toilet five times per day (5). Let’s be generous and say everyone is using 1.6 GPF toilets. That still comes to 8 gallons/day per person down the drain (literally). And for a four-person household, it comes to 32 gallons per day.

Why all the flushing? In short, people use way more paper than they’re supposed to. You’re supposed to need something like 5 squares for a bowel movement but people are rarely that frugal.  

According to one survey, almost half of TP users wad, crumple, or wrap their paper which almost certainly means using more toilet paper than needed. 

I know I did before making the switch to a bidet—for me, it was because I didn’t want to get poop on my hands, and using extra paper provides a nice barrier.  

By using little to no paper, it follows that far less flushing would be needed throughout the day. Unlike public restrooms, residential properties have weaker plumbing and require more flushing to prevent clogging. 

And to the extent that bidets result in less flushing, they can save the user a ton in the long term.  

This benefit applies doubly in a couple of different situations. 

Those with Gastrointestinal Issues 

Even with the most severe GI issues, stool size alone rarely calls for extra flushing. It’s all the extra toilet paper that comes with big bowel movements that often requires another flush or two.  

If you eliminate TP from the equation, one flush per bowel movement is all you’ll ever need. 

As we talked about in the articles on bidet benefits for constipation and diarrhea, some GI problems, especially diarrhea and bowel incontinence, lead to frequent bowel movements which leads to frequent wiping.  

Depending on the severity of the issue, this can double or triple your average TP use which means having to double or triple your flushing frequency. 

Those with Weak Toilets and Plumbing 

There are several types of toilets each with its own benefits and drawbacks. As with other aspects, not all toilets are created equal when it comes to clearing the bowl in a single flush. The more TP that’s in the bowl, the more challenging it is to flush it all down.  

This is one reason why bidets are great for septic tanks.

Recommendations vary, but a common rule of thumb for toilet paper usage is around 4 to 5 squares of 2-ply TP per flush. If you use moist wipes, then heaven help you—most packages recommend flushing with each square.  

I doubt many people follow those guidelines because most toilets can handle more toilet paper than 4-5 squares. But for those whose toilets can’t handle much TP, getting by with only one flush can be challenging. For a lot of people, passing the white glove test after 4-5 squares is a pretty tall order.  

If you don’t flush enough, you can clog your toilet—even if a toilet doesn’t clog, it can still fail to clear all solid waste from the bowl. In some cases, this true even when the bowl’s contents are minimal.  

If you flush multiple times, you end up using gallons of water driving the utility bill up.  

What if you didn’t have to wipe? By using a bidet, you can get by with a single flush no matter the quality of the toilet you’re using.  

Bidets have their own plumbing requirements. But as we’ll cover below, they use much less water than most bathroom appliances. 

Most Modern Bidets Use an Aerated Spray  

Nowadays, most faucets have an integral device that aerates the water that passes through the nozzle.  

This is true for the faucets on sinks and standalone bidets as well as the wands/nozzles on both modern bidets that attach to toilets. It’s probably true of handheld sprayers too.

By incorporating air into the water stream, you use less water while getting an equally effective clean.  

You might be wondering how bidets can provide a decent clean if they don’t spray much water. Cleaning has more to do with the amount of water pressure and the precision in aiming the nozzle. Some models are better at aiming than others. 

Shorter Cleaning Sessions Use Less Water

You can control the duration of the cleaning session. For maximum water savings, try not to clean for any longer than necessary.  

Most electric bidets spray for a minute unless programmed otherwise. But a lot of users find that they’re clean at the 30-second mark.  

This will take some experimentation but once you find what you can get by with, most modern bidets will allow you to save the settings in what they call “user presents.” 

Bidets Use Much Less Water These Days

Using modern technology, high-tech bidets get by with a lot lower spray volume while maintaining sufficient water pressure to get an effective clean. 

It depends on the model, but a common spray volume and pressure put out by electric bidets is about 0.1 gal/min. Since most cleaning sessions last about 30 seconds to a minute, each session should use no more than 0.05-0.1 gallons overall. 

Electric bidets use less water while still cleaning as effectively as non-electric units. Bidet attachments tend to use more water in comparison but are getting more efficient these days. 

While non-electric bidets use the home’s water pressure to spray (resulting in a stronger jet and more water), electric bidet seats use a motor to propel water through a nozzle. Hence, the different ranges in water pressure.  

Bidet sprayers can go through a lot of water if the user isn’t careful. Handheld bidets use a larger stream of water (or multiple small streams) and I’ve heard rumors that some models can spray water at pressures well over 100 PSI. Of course, you can control the pressure by not squeezing so hard.  

At the very least, non-electric bidets should be expected to provide at least 40-60 PSI of pressure because that’s the range most homes provide both cold and hot water appliances. The max pressure is further enhanced by the bidet design.

With modern electric bidets, you get consistent pressure with the turn of a dial or the touch of a button. Not all models provide enough pressure to get an effective clean.  

Some are downright lackluster in this respect. In my experience, brands like TOTO and Brondell provide the best clean while keeping water pressure to a minimum. 

Do Bidets Save Water? Conclusion

So, there you have it.

Bidets do save water. The small amount of water used by bidets is far surpassed by the amount saved due to the downward shifting demand for toilet paper. Bidet use is already saving millions of gallons of water annually and has the potential to save even more as the trend continues.

For maximum water savings, get a model with a moderate water pressure and aerated jet stream. A warm air dryer is also useful for further reducing TP use which has the downstream effect on saving trees and water.

That’s it for now. Thanks for reading.

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