What is the Best GPF for a Toilet?

Buying a toilet is not as easy as it looks. While all toilets may seem the same, they vary in height, shape ,and flushing system.

One of the most common differences in toilets is the water consumption and the rate per flush (or gallons per flush). Knowing about GPF will help you select the right toilet for your household and understand how the water consumption of your toilet can affect water bills.

In this article, we’ll take a look at the different types of toilets on the market and how to choose the best GPF for your needs.

What is GPF?

GPF stands for ‘gallons per flush’ which refers to the amount of water used by a toilet each time it’s flushed.  A typical toilet has a flushing capacity of 1.6 GPF or 1.28 GPF which means that it uses 1.6 gallons or 1.28 gallons of water per flush.

To check the GPF of your current toilet or the model you’re purchasing, lift up the lid of the tank and check the underside. Some models indicate how many GPF they use, while others only indicate the year of manufacture.

Toilets manufactured before 1992 didn’t have water restrictions, and used several gallons of water per flush, resulting in excessive wastage of water.

Types of Toilets

Different types of toilets have different flushing capacities. Here are some of the most common types in use today

1. Dual-Flush Toilets  

One-piece dual-flush toilet by Swiss Madison Well-Made Forever Store. See it here.

Dual-flush toilets have two different flushing options – a full flush and a half flush. The full flush is used for solid waste, while the half flush is for liquid waste. These toilets are highly water efficient and environmentally friendly, which is why they’re used in many countries with water shortage issues. They tend to use around 0.08 to 1.1 gallons per half flush and around 1.2 gallons per full flush

2. Gravity-Flush Toilets

gravity flush toilet
Gravity-Flush Toilet by the AW Store. See it here.

These toilets are mostly used for motorhomes, campervans and portable toilets . When the flush pedal is pushed, the tank drops the water into the toilet bowl, pushing all the waste through its trap way. Gravity toilets are silent, easy to maintain, and are less likely to clog.

3. Pressure-Assisted Toilets

pressure assisted toilet
Pressure-Assisted Toilet by the American Standard Store. See it here

Pressure-assisted toilets have a powerful flush, which is their biggest advantage. When the flush button is pressed, the pressurized air inside the tank forces the water into the toilet bowl. A single flush, which averages about 1.1 gpf, is usually sufficient to clear the bowl completely, leaving no residue behind. These toilets are perfect for powerful, clog-free flushing action, but they’re also quite noisy.

4. Double Cyclone Flush Toilets

Double Cyclone Flush Toilets

Double Cyclone Het Bowl by TOTO. See it here.

New to the market, double cyclone flush toilets use less water and are considered to be eco-friendly. They’re not as water-efficient as the dual-flush toilets, but they use a significantly less amount of water per flush (around 1.28) in comparison to other single-flush models and can have a positive effect on your water bills.

Toilet Models and GPF

Older toilet models used more water (about 5-8 GPF). With the advancement of technology, and with increasing restrictions on water usage, newer and more water-efficient models have been created. Since 1992, all older models were replaced with 1.6 GPF throughout the U.S. Today, the 1.6 GPF model is being replaced by newer models that use 1.28 GPF and are made with extra comfort features, as well as a better and more effective flush system.


american standard toilet
1.28 GPF Dual-Flush Toilet by American Standard Store. See it here.

Overall, the 1.28 GPF toilet models are highly effective, and are an environmentally friendly option. They’ve become extremely popular since they were first introduced.

kohler toilet
1.6 GPF Toilet by the Kohler Store. See it here.

Both the 1.28 GPF and 1.6 GPF toilet models are similar in functionality. However, each model has its own advantages and disadvantages.

Pros of Using 1.28 GPF Toilet

  1. Save Water: By using this toilet model, you can expect to save around 3000 to 4000 gallons of water every year.
  2. Save Money: Since your toilet uses less water, it will help you cut down on your water bills.
  3. Enjoy a Rebate: Some states in the U.S. offer discounts for using the 1.28 GPF toilet, so you might be able to enjoy a rebate when you buy yours.
  4. Quiet Flush: This toilet model has a quieter flush than the 1.6 GPF model.

Cons of Using 1.28 GPF Toilet

  • Low Powered Flush: Since these toilets use less water to flush, they have lower flushing power which means you may experience clogging and stains in the bowl over time.
  • Additional Flushes May Be Required: In case of clogging, you may have to flush more than once, resulting in extra water consumption.

Pros of Using 1.6 GPF Toilet

  1. More Powerful Flush: These toilets are far more effective than the 1.28 model. There’s no clogging and instead of leaving behind stains, they clean them up.
  2. Usually Quiet: They’re almost as quiet as the 1.28 models.
  3. One Flush is Enough: One flush is enough to get rid of heavy wastes.
  4. Saves Water Overall: Since you won’t need to flush this toilet twice like the 1.28 model, you’ll be saving a lot of water.

Cons of Using 1.6 GPF Toilet

  1. Consumes More Water Per Flush: Although this model saves water by eliminating the need for additional flushes, it consumes more water with every flush.
  2. Bulky Design: These toilets typically have a larger tank.
  3. Not Permitted in Some States: In the U.S., the 1.6 GPF toilet is only permitted in some states.

How to Choose the Toilet with the Best GPF

Unless you live in a state that only permits the 1.28 GPF toilet, select the GPF depending on your daily needs. If you live in a large household with many toilets and need to cut down on water consumption and bills, consider the 1.28 GPF toilets. However, if you have only one or two toilets in your home, you can go for the 1.6 GPF models instead.

While GPF is important, the brand of the toilet you buy also plays an important role in its effectiveness and durability. Some brands focus on flush power and high performance whereas others focus more on comfort and the appearance of the model.

If you live in a state where the 1.6 GPF toilet is not permitted, you will then have to purchase toilets with 1.28 GPF or lower. In states such as California, Georgia, New York and Texas, the GPF of a toilet cannot exceed 1.28.

Most U.S. states reward homeowners with a rebate when they replace a higher GPF toilet with the 1.28 models to encourage the practice of saving water. Due to these regulations, an increasing number of homeowners are replacing their toilets with the new models.

In Brief

When choosing the GPF of your toilet, it’s important to consider water consumption and sustainability, but also practicality for your home. The 1.28 GPF toilet generally gives you the best balance between the two, but there are toilets with lower GPF, which can make a huge impact over time in terms of water saved.

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