Toilets with 1.28 Vs 1.6 GPF: A side-by-side comparison

From the looks, you might think that all toilets are the same. But this is far from the truth as they have a lot of variations(Like Comfort height vs Standard height, 1 Piece vs 2 Piece, Round vs Elongated, Dual Flush VS Single Flush). And one of the major differences in flushing toilets is their water consumption rate per every flush. Some use 1.6 gallons of water per flush while others use 1.28 gallons of water per flush. Read this 1.28 VS 1.6 GPF Toilets article to find the difference between them.

The first flushing toilets used 3.5 to 5 GPF, which was later replaced by 1.6 GPF in 1994. But with the pressure to save more water, the high-efficiency and ultra-high-efficiency toilets that use 1.28 GPF and 0.8 GPF, respectively, have been introduced again.

Features Comparison: 1.28 VS 1.6 GPF Toilets




Water Consumption:1.28 Gallons Per Flush1.6 Gallons Per Flush
Water Saving:YesNo
Powerful Flush:NoYes
1 Flush Enough?Sometime may need two flush1 Flush is Enough
Space Saving:YesNo
Laws:USA all States AllowA few USA States Don’t Allow
Bowl After Flush:CleanMarginally More Clean


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On the contrary, this doesn’t mean that the latest toilets with a lower water usage rate aren’t effective as some ultra-high-efficiency toilets can push down up to 800 grams of solids in a single flush.

Laws about the Toilet 1.28 and 1.6 GPF

In some states, you may stand to get a rebate when you switch from the old high water consumption toilets to the 1.28 GPF toilets. As a matter of fact, switching to high-efficiency toilets that use 1.28 GPF or less will help you save 27, 000 gallons of water per year.

States such as California, Colorado, and Texas require homeowners to install toilets that use only 1.28 gallons of water per flush or less, while Georgia requires you to install WaterSense toilets if you’re renovating or building your home. Other places like Nevada, Washington, New York, and Connecticut need you to maintain the federal standard of 1.6 gallons of water per flush or less.

In 1995, the National Energy Policy Act started requiring plumbing manufacturers to make and homeowners who were remodeling their homes to purchase toilets that utilized 1.6 gallons of water per flush or less.

If you’re undecided about which toilet to choose between the 1.28 GPF and 1.6 GPF toilets, then you’ve come to the right place. In this post, we’ll talk about their features, pros, and cons so that you can have an easy time choosing between the two toilets.

1.28 GPF Toilet

With the need to save more water for an eco-friendly environment, manufacturers have come up with high-efficiency toilets that help you save more than annually. 1.28 gallons per flush toilets are becoming very popular by the day as they use less water than the recommended 1.6 gallons per flush but are still very effective in clearing waste.

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  • You will save at least 4, 000 gallons of water annually
  • You may stand to get rebates in some states if you install them


  • Have more cases of staining and clogging
  • Most of them don’t clear a large mass in one flush

1.6 GPF Toilet

This is the federal standard but it is not recommended in some states like California and Texas. Toilets that feature a 1.6 GPF are more effective as they clear waste easily in just a single flush. However, even though these toilets use more water, they don’t leave behind stains or have to be flushed twice to clear waste like in some 1.28 GPF toilets.

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  • Most of them clear a large mass in one flush
  • The toilet experiences fewer clogs and stains


  • They consume more water than their counterpart

Which is Better? 1.28 or 1.6 GPF?

Depending on where you live, you may find one of these toilet models to be ideal for you. Regardless of which toilet you choose, ensure that you go for the one that meets your needs. If you want to save water, then I would recommend the 1.28 gpf toilet, but if you want a more effective powerful flush toilet, then you should go for the 1.6 GPF toilet.

All-in-all, these two toilet models are amazing in performance and will help you save water to some extent. Consider other features so that you can end up with a toilet that meets your needs and demands.


Question: How many times does an average American flush the toilet per day?
Answer: It is estimated that an average American lushes about 5 times a day, which adds really fast. Since the introduction of water-efficient toilets, it has been estimated that there is a 74% reduction in average water use by toilets in the USA since the 1980s. When you replace a standard 1.6-gallon per flush toilet with an ultra-high-efficiency toilet of 0.8 GPF, then you end up saving at least 5, 840 gallons of water yearly.

Question: Is it okay if I buy from any toilet brand?
Answer: No, it is not. First and foremost, you have to perform your own research so that you can end up with a toilet that meets your needs. Some toilets are known for their comfort, while others are known for their performance. Ensure to go through reviews and know which brands are outperforming the others. Brands such as Toto, American Standard, and Kohler are known for their comfort, power, and durability.

Hi, this is Robert Crossan, the owner of this website, has 17 years of experience in the installation, maintenance, and repair of toilets and plumbing systems. After completing the Level 2 Basic Plumbing course in 2005, I started working in both domestic and commercial buildings as a professional plumber. So I can figure out the core difference between different toilet models and brands. It also helped me monitor their work performance and setbacks.


  1. Your calculations for an average American are not accurate unless you are assuming an entire family of four. 1.6 gals x 5 per day x 365 days= 2920 gals/year. Cutting that in half with a 0.8 gpf = 1460 gals/year.

  2. Four people x 5 flushes a day = 20 flushes x 365 days a year = 7,300 flushes per year.

    The article talks about going from a 1.6 gallon flush down to 1.28. For the calculation, 0.8 is used. Let’s stick to 1.28. The savings is 0.32 gallon per flush.
    1.6 gallon – 1.28 gallon = 0.32 gallon saved per flush.

    Annual savings for a family of four: 7,300 flushes per year x 0.32 gallon water saved = 2,336 gallons saved per year.

  3. I have an American standard that flushes 1.6gpf. It was advertised to flush golf balls. However, it’s a yr old and I have replaced O ring a bell rubber washer 3 x. And it still continues to leak. And recommendations?

    • I will not be able to provide an exact solution without seeing the toilet. In this case, contact American Standard support: 1 (800) 442-1902. Their support is good, and they might help you to solve the leaking issue.

  4. This article has been extremely useful – we are purchasing toilets for new construction and this is just what we needed.

    Great article! Much appreciated.

  5. Why have you not included Coro-na toilets in the review? Australia has the worst water issue of any industrialized country. It is expensive do to shipping costs, but is very effective, no clogs due to a bit short of a 4″ diameter trap way. It may have issues flushing large naval oranges, grapefruit and large russet potatoes. Golf balls are not a problem but ping pong balls may be unless they are perforated reducing the natural ability to float.

  6. If you have to flush a 1.28 gallon toilet twice the you are using 2.56 gallons per day for each family member who does number 2.
    2.56 x 4 = 10.24 gallons per day.
    1.6 gallons x 4 = 6.4 gallons per day.

    Then ad 3 flushes for each person for number 1.

    1.28 x 3 = 3.84
    3.84 + 10.24 = 14.08 gallons
    1.6 x 3 = 4.8
    4.8 + 6.4 = 11.2 gallons

    The 1.28 gallon toilet ACTUALLY ISES MORE WATER than the 1.6 gallon toilet, because of required double flushing once a day.

    • You forgot to multiply the flushes for number 1 by the number of people. That can drastically change your calculations.

      You seem to be working off an assumption that it will be used 4 times per day per person – three #1 and one #2. That differs from the article’s estimate of 5 times per day but let’s go with that. I’m going to go with flushes per day per person for simpler calculations.

      1.28 gpf x 5 flushes per day per person = 6.4 gallons per person per day
      1.6 gpf x 4 flushes per day per person = 6.4 gallons per person per day

      So it’s a tossup with those numbers, which I think are a bit conservative for the number of uses for most families. With more #1, savings increase. With the article’s 5 usages per day, assuming one double flush a day per person, a family of 4 could save 467 gallons a year. So where allowed by law, every household should consider their own needs. If everyone is out of the house for most of the day and everyone takes their #2 at home, the 1.6 may be the best option.

      That said, if every toilet in the country was converted to a 1.28, overall water usage would be reduced regardless, and that’s the entire point. But I acknowledge at the household level, that may not be the case.

  7. I’m not sure why the entire country is being considered. I live in septic and well country. I don’t use a city supplied water supply. My septic filters in 6 feet of soil (that’s generally all that is needed for water to be filtered). Much of that filtered water goes back to the aquifier. The low flush toilets for the most part do not clean a toilet, and do not flush in one flush many times for number 2. Our laws are being imposed for people on systems, not people in rural areas. There should be more flexible laws that fit the needs..
    Now since I can’t change the laws, maybe the manufacturers should optimize their systems so they actually work. In europe, they have a 2 button system, one low volume for #1 and a higher volume for #2… seems reasonable.. seems to almost work, although I have had to double flush in europe as well.

  8. I have a 1.6 toilet and my son across the street has a 1.28. The women in his family have to flush twice for #1 and the entire family, (male/female) have to flush at least 3 times for #2. At least twice a month the toilet gets clogged and they have to come to my house to use my toilet until theirs get fixed. They are not large people, all 4 of them are on the thin side.

    In my house, we flush the toilet ONCE for #1 and #2 regardless of gender and my toilet has never clogged. My son wants to replace his toilet with a 1.6 but here in Calif. it is hard to find.

    I will NEVER use a 1.28 toilet. There isn’t enough money in the world to make me use a 1.28 toilet. The environmentalist can keep their baby toilets, feeling proud of themselves while they waste water with every second flush.

  9. Thankfully with newer technologies outside of gravity fed toilets are available. Kohler, American Standard and Toto are the big three. The real solutions that we are using are much better flushing technologies like powerful systems like pressure assist, siphon systems, cyclone, canister, tornado etc. These are all mostly branded technologies and all for the most part better than any gravity fed system. I personally prefer the pressure assist systems from Flushmate found in those big brand names like Kohler and American Standard. Since I live in state that gets to “dictate” if I can have a 1.6gpf toilet, I just order online. I am all for conservation of water but not when in reality there is no real savings. ALL 1.28gpf and .8 gallon toilets are worthless since you have to flush twice or three times UNLESS you have an upgraded flushing technology system in the toilet tank. I know this because we have tried them and they do not work on the low gallons per flush basic toilets. You basically need a commercial grade flushing system, if you are going to be forced use a cup of water to flush a large stool or large amounts of toilet paper. Either way, 1.0gpf is also now available here also, but I have not tried it, because I see it as equally as worthless because they did not change anything else. They are a complete waste of water for a full family or just a couple of people constantly flushing over and over. But remember, the upgraded flushing systems come at a bigger financial cost as the toilets are quite expensive, but mine have been great so far. I have tried three different designs and they are definitely an upgrade from the old days. Just a quick Google search will find YouTube videos and then you can buy from Lowes, Home Depot, Amazon or whatever home store you prefer. No, I do not live in California either. But you can expect to pay $400-800 easy for one of these better toilets. That is the only way these low flow toilets will ever be viable as real options for water savings. I would make some suggestions everyone has a different setup, design or need.

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