1.28 GPF vs 1.6 GPF Toilets: Which Is Better?

You might not think often about how much water is used to flush toilets, but the amount of water in GPF toilets can have a strong effect on your water bill. Today, the standard for water usage is 1.6 gallons per flush.

In the past, toilets would flush up to eight gallons of water at a time.

While the 1.6 gallon flush is a massive improvement from years past, there are toilets with even better water efficiency. This type of toilet aims to create a powerful flush using just 1.28 gallons.

There are different designs that use less water, and the right one for you will vary.

Benefits of a 1.28 GPF Toilet 

Toilets that use 1.28 gallons per flush are available in every shape and size. You can purchase them with all the features and amenities of a standard toilet.

Maybe you want a comfort height seat, or a one-piece design, or a better flushing mechanism. No matter the case, there’s a toilet to suit your needs.

The main point of a 1.28 GPF design is that it has lower water consumption. In addition to saving on your water bill, this is an eco-friendly option endorsed by the EPA.

These water-saving toilets are WaterSense certified, meaning they’ve passed the certifications for the EPA’s WaterSense program.

The average person will flush the toilet five times a way. So water-efficient toilets can save two gallons per person.

If you have dual flush toilets, the flushing system allows you to save even more water with liquid waste.

With solid waste, you still get enough single flush power to avoid needing to flush twice.

If you have a multi-person household, high-efficiency toilets can save thousands of gallons of water every year.

The only potential drawback is that sometimes low-flow toilets aren’t powerful enough for solid waste. This may make low flush toilets more likely to clog.

However, as mentioned, many toilet manufacturers have special flushing technology to mitigate this problem.

Low flush toilets are also quieter than their standard counterparts. If your toilet tank makes massive noises in the middle of the night, you might appreciate a change.

Benefits of a 1.6 GPF Toilet 

The main benefit of a 1.6 GPF option is that you get more volume when you flush. That can make it easier for solid waste to move through the pipes without a double flush.

However, this design also wastes water. Depending how often your family needs toilet uses, you could be wasting multiple gallons a day.

The federal government set the 1.6 gallon standard with the Energy Policy Act in 1992. But 30 years have passed since then, and the technology for energy efficiency has increased significantly.

Let’s take a look at a few of the best toilet options for people needing a new porcelain throne. These are mostly available for purchase on Amazon.

If you live in states like Colorado, Texas, California, and Georgia, you may be eligible for rebates based on water efficiency.

Best Toilets for Water-Efficient Flushing

Kohler K-3999-0

Kohler K-3999-0

This 1.28 GPF design has everything you need in a toilet. While the design is fairly standard,

Kohler toilets are known for having advanced technology.

This toilet is built with a comfort height seat, which is taller than standard seating. Comfort height seats are ADA-accessible, and they’re preferred for people with mobility issues.

There is also an elongated toilet bowl, which is more comfortable to sit on for long periods of time.

Sitting down and standing up are both simple thanks to the height. The toilet is also particularly easy to install because the tank bolts come pre-installed.

This design does have the WaterSense certification from the EPA. Thanks to the patented Class Five technology, the flush valve removes a huge amount of bulk waste.

The bowl stays clean, needing less maintenance in general.

Just keep in mind that the toilet comes without a seat, so this needs to be purchased separately.

Toto Eco UltraMax One-Piece

Toto Eco UltraMax One-Piece_a

If you have a little more room in your budget, you might consider the UltraMax from Toto. This one-piece toilet also has a high seat and an elongated bowl, making it super comfortable to use.

It boasts all the same advantages as the Kohler.

The toilet bowl is glazed with SanaGloss, a patented barrier that keeps materials from sticking to the surface. This makes it even easier to keep the bowl clean.

The design includes a soft-closing seat, so you don’t need to worry about waking anyone up with the lid.

The UltraMax flush system has a large siphon jet that creates massive pressure around the inside of the bowl, dislodging solid waste. It also has a 3-inch valve that’s wider than the standard.

This allows more waste to flow through the pipes without clogging.

Not only is the flush system powerful, but it’s also quiet. Once again, you don’t need to worry about waking people up in the middle of the night.


When you’re comparing 1.28 GPF to 1.6 GPF, the biggest factor is water efficiency. If your toilet uses less water to flush, you’ll save thousands of gallons over the toilet’s lifespan.

That’s great for both the environment and your wallet.

Some people prefer 1.6 GPF designs because of the increased volume. Extra volume can sometimes help keep the toilet cleaner and move waste more easily.

But if you have a design like the Toto UltraMax, the flushing system is powerful enough to mitigate that.

Overall, there are far more advantages to a 1.28 GPF toilet than disadvantages. Just make sure you get a design that has the technology that’s right for you.