At first glance, all toilets may seem the same, but they vary(Like Comfort height vs Standard height, 1 Piece vs 2 Piece, Round vs Elongated, Dual Flush VS Single Flush) significantly in design, efficiency, and water consumption. One of the most important distinctions is their gallons per flush (GPF) rating. Some flushing toilets use 1.6 gallons of water per flush, while others consume only 1.28 gallons of water per flush. This comparison of 1.28 VS 1.6 GPF toilets will help you understand the differences, benefits, drawbacks, and laws regulating water usage. Keep reading to choose the best toilet for your home!
The Evolution of Water-Efficient Toilets:
Originally, flushing toilets used between 3.5 to 5 gallons per flush (GPF). However, in 1994, 1.6 GPF toilets became the new standard under the National Energy Policy Act to reduce excessive water usage.
With growing environmental concerns, high-efficiency toilets (HETs) using 1.28 GPF or even 0.8 GPF were introduced. These newer models help conserve water while maintaining flushing effectiveness.
Feature Comparison: 1.28 VS 1.6 GPF Toilets
| Feature | 1.28 GPF | 1.6 GPF |
|---|---|---|
| Water Consumption | 1.28 Gallons Per Flush | 1.6 Gallons Per Flush |
| Powerful Flush: | No | Yes |
| Water Saving | Yes | No |
| Flushing Power | May require a second flush occasionally | Clears waste in one flush |
| Noise Level | Quieter | Quiet |
| Eco-Friendly | Yes | No |
| Bowl Size | Smaller | Larger |
| Space-Saving | Yes | No |
| Legality | Allowed in all U.S. states | Restricted in some states |
| Popularity | Increasing | Decreasing |
| Bowl Cleanliness After Flush | Clean | Slightly Cleaner |
| My Recommendation | Check Today’s Price | Check Today’s Price |
Some assume that toilets using less water are less effective, but this is not always the case. Ultra-high-efficiency toilets (UHETs) with 1.28 GPF or lower can flush up to 800 grams of solid waste in a single flush, proving their efficiency.
U.S. Laws on 1.28 GPF and 1.6 GPF Toilets
In some states, homeowners may qualify for rebates when switching from high-water consumption toilets to 1.28 GPF models. In fact, upgrading to high-efficiency toilets (HETs) that use 1.28 GPF or less can save up to 27,000 gallons of water annually.
Several states have implemented water conservation laws to regulate toilet water usage:
- California, Colorado, and Texas mandate that homeowners install toilets that use 1.28 GPF or less.
- Georgia requires the installation of WaterSense-certified toilets for new constructions and renovations.
- Nevada, Washington, New York, and Connecticut enforce the federal standard, which limits toilet water consumption to 1.6 GPF or less.
Since 1995, the National Energy Policy Act has required plumbing manufacturers to produce and homeowners remodeling their homes to purchase toilets that use 1.6 GPF or less, promoting water efficiency nationwide.
If you’re unsure whether to choose a 1.28 GPF or 1.6 GPF toilet, this guide will help you compare their features, pros, and cons, making it easier to select the best option for your home.
1.28 GPF Toilet: Pros & Cons
To promote water conservation and environmental sustainability, manufacturers have developed high-efficiency toilets (HETs) that significantly reduce water usage. 1.28 GPF (gallons per flush) toilets are gaining popularity because they use less water than the standard 1.6 GPF models while remaining highly effective at clearing waste.
Our Recommendation
Pros:
✅ Saves at least 4,000 gallons of water annually
✅ Possible rebates in some states
✅ Eco-friendly and reduces water bills
Cons:
❌ Higher chance of staining and clogging
❌ May require multiple flushes for large waste loads
1.6 GPF Toilet: Pros & Cons
1.6 GPF toilets are the federal standard, but they are not recommended in certain states, such as California and Texas, due to water conservation laws. These toilets are highly effective, as they can clear waste in a single flush. Although 1.6 GPF models use more water, they reduce staining and minimize the need for multiple flushes, unlike some 1.28 GPF toilets, which may require a second flush to fully clear waste.
Pros:
✅ Powerful flush clears waste in one go
✅ Less clogging and staining compared to 1.28 GPF models
✅ More effective for larger households
Cons:
❌ Uses more water, leading to higher water bills
❌ Restricted in some states due to water conservation laws
Which is Better: 1.28 GPF or 1.6 GPF?
Choosing between a 1.28 GPF and a 1.6 GPF toilet depends on your needs and location:
💧 Choose a 1.28 GPF toilet if:
- You want to save water and lower utility bills
- You live in a state that requires water-efficient toilets
- You are eligible for rebates
🚽 Choose a 1.6 GPF toilet if:
- You prefer a stronger flush to avoid multiple flushes
- You live in a state where 1.6 GPF toilets are allowed
- You have high toilet usage in your household
Regardless of which option you choose, ensure that the toilet meets your household’s needs while adhering to state regulations.
FAQs: 1.6 GPF and 1.28 GPF Toilets
1. How many times does an average American flush the toilet daily?
The average American flushes the toilet 5 times per day. Since the introduction of water-efficient toilets, there has been a 74% reduction in household water use since the 1980s. Switching to an ultra-high-efficiency toilet (0.8 GPF) can save over 5,840 gallons of water yearly.
2. Can I buy any toilet brand?
No, it is essential to research toilet brands before purchasing. Some brands prioritize comfort, while others focus on performance and water efficiency. Brands such as Toto, American Standard, and Kohler are well-known for their reliable, high-performance toilets.
3. Do 1.28 GPF toilets clog more often?
In some cases, yes. Lower water volume may lead to occasional clogs, but modern flush technologies compensate for this by improving waste removal efficiency.
4. Do all U.S. states allow 1.6 GPF toilets?
No. California, Colorado, and Texas require homeowners to install 1.28 GPF toilets or lower. Other states follow the federal standard (1.6 GPF or less).
5. Can I get a rebate for switching to a 1.28 GPF toilet?
Yes! Some states and cities offer rebates for installing WaterSense-certified 1.28 GPF toilets to encourage water conservation.
Final Thoughts
Both 1.28 GPF and 1.6 GPF toilets have their own advantages and disadvantages. If water conservation and savings are your top priorities, a 1.28 GPF toilet is the best choice. However, if you want a powerful flush with minimal clogging, a 1.6 GPF toilet may be more suitable.
Ultimately, consider your state laws, household needs, and budget when choosing the right toilet for your home.
Still have questions after reading this 1.28 VS 1.6 GPF toilet article? Comment below.
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.
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.
Yes.
1460 x 4(family of four) = 5,840 gallons/Year.
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.
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.
Check for cracks where wax ring installs,,no cracks,use double thick wax ring ..should do the job!
This article has been extremely useful – we are purchasing toilets for new construction and this is just what we needed.
Great article! Much appreciated.
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.
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.
Vs.
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
Vs.
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.
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.
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.
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.