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How Much Water Does It Take to Flush a Toilet? Facts & FAQ

flushing water in white toilet bowl

If you have ever wondered how much water it takes to flush a toilet, you are not alone. Some people want to know how much water their toilet uses to try and help reduce water usage. Other people are simply curious about how toilets work. The amount of water a toilet uses depends on a number of factors, but the most important one is the age of your toilet. Older toilets use much more water than newer toilets.

The average toilet uses 1.6 gallons of water per flush. That is because the amount of water a toilet is allowed to use is regulated by the federal government.
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The Average Toilet

The current regulation monitored by the Environmental Protection Agency is 1.6 gallons. That might not sound like a lot, but toilets account for the largest single source of water usage in a typical American home. Toilets account for 30% of a home’s total water usage beating out showers, washing machines, and dishwashers.

If you have a newer model toilet, there is a good chance that it abides by the 1.6 gallons per flush regulations that are currently in place.

Flushing toilet
Featured Image Credit: Marco Verch Professional Photographer and Speaker, Flickr

New Toilets

The newest toilets have managed to cut their water usage even further. The most efficient toilets now only use 1.28 gallons per flush compared to 1.6 gallons used by the typical toilet. The difference might not sound like much, but it accounts for a 20% decrease in water usage over the course of a year. That can add up to hundreds, if not thousands, of gallons of water saved over the average toilet.

Old Toilets

Older toilets were much less efficient than new toilets. Old toilets used as much as 7 gallons per flush. Many old toilets averaged 6 gallons per flush, which is five times as much as modern toilets use. Old toilets accounted for a massive amount of water usage and a large amount of wasted water.

toilet flushing
Image Credit: Am.p, Shutterstock

In An Emergency

In an emergency, you can get away with using less water per flush if necessary. You may have heard the advice to fill your bathtub with water ahead of an oncoming storm or severe weather event where you are expected to lose power. This is because the water in your tub can be used to flush your toilet when the power is out.

If the tank is full, you can flush your toilet once, but then you will have to refill the tank with water from the bathtub. If you are just trying to flush your toilet once when the power is out, you can put enough water in the tank to just cover the seal at the bottom, but the bowl might not fill. If not, you will need to account for 1.6 gallons per flush to keep your toilet running when the power is out.

The standard bathtub holds 42 gallons of water when full, so you can get 26 flushes in an emergency. This can cut down the stress of having no water and power after a storm by allowing you to use the bathroom relatively normally.

man flushing toilet
Image Credit: son Photo, Shutterstock

How To Tell How Much Water Your Toilet Uses

Many toilets have a stamp on them somewhere that will let you know how much water it uses. The stamp can sometimes be found inside the bowl, but most often, it is found inside the tank. The water usage is often displayed alongside the logo, brand, or model number of your particular toilet.

Water usage is represented by the acronym gpf, which stands for gallons per flush. A typical stamp will say something like Kohler 1.6 gpf, which lets you know how much water the toilet uses every time you use it. Sometimes the stamp will have worn away over time or be located somewhere that you can’t easily find.

You can also look up your toilet’s brand and relative age and use a water calculator to get a rough estimate of how much water your toilet is using on a regular basis.

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If you have annoyingly high-water bills, you could be suffering from an old toilet. Old toilets use far more water than new toilets. It might make sense to upgrade to a more efficient toilet if your water usage continues to be far above where you want it. Toilets are the primary source of residential water use, and your toilet uses 1.6 gallons per flush every time you utilize it.


Featured Image Credit: Karolina Grabowska, Pexels


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