1.28 vs 1.6 GPF toilets: Overview and Comparison

Most buyers consider a toilet’s flushing power or water efficiency. Many people are not willing to flush twice or more. In this regard, you should consider the 1.28 vs 1.6 GPF toilets that are currently available in the United States.

Purchasing a new toilet may appear to be a simple decision at first. However, there are a few things you should think about before going to the store, especially if you live in a drought-prone state.

The flush power of a toilet is more important than ever today. High-efficiency or low-flow toilets have a GPF (Gallons per Flush) of 1.6 to 1.28 or less, though these two are the most common. Do you want to know why there’s a difference in the digits? A 1.6 GPF toilet requires 1.6 gallons per flush, while a 1.28 GPF toilet requires 1.28 gallons.

So, which is better, 1.28 GPF or 1.6 GPF toilets? It ultimately comes down to whether having a toilet with a higher flush power or one that can save water at a higher rate is more important to you. The amount of flush power in your toilet will undoubtedly affect your water bill and the overall condition of your home’s plumbing system, especially if you have more than one toilet or a large household.

However, the flushing capacity of a toilet tank is not solely determined by water consumption. Other factors are incorporated alongside it. Let’s take a look at what GPF means and how much effect it has on the flushing capacity of a toilet.

What is GPF and Why Is It Important?

GPF stands for the required gallon per flush when flushing the toilet. Because older toilets have a higher GPF than newer ones, they are harmful to the environment. The National Energy Policy Act was first implemented in 1992 in order to save water supply. To comply with this regulation, GPF should not be greater than 1.6.

Lower GPF toilets, such as 1.28 GPF toilets, have recently become popular and can be found in the majority of toilets and households. With the growing popularity of 1.6 GPF toilets, each household can save approximately 20,000 gallons of water per year. The advancements in toilets with 1.28 GPF and larger flush valves save 50% of the water.

The amount of water used to flush a toilet is measured in gallons per flush (GPF). While many people do not consider this toilet feature, it is extremely important. Older toilets have a higher GPF than modern toilets, making them more wasteful and unfriendly to the environment.

Water conservation is critical, but it also comes down to money. If a toilet uses too many GPF, it is wasting money and literally flushing money down the toilet. The EPA has been in effect since 1992 as a means of conserving water.

The cost savings associated with high-efficiency toilets are directly proportional to the amount of water they are known to save. A household family could save up to 20,000 gallons per year after installing 1.6 GPF flow toilets. Switching to high-efficiency toilets like these has cut water consumption by half. These statistics add up, and as the 1.28 GPF toilets improve, the statistics will improve even more.

History of Low Flow Toilets

The Energy Policy Act of 1994 mandated the installation of energy-efficient toilets. Why? Because the United States government desired to enact a policy that would aid in the preservation of water in the country, particularly in states that are prone to drought, such as those in the western and southern regions.

Prior to the invention of these toilets, the average toilet used anywhere from 3 to 7 gallons for one flush. Over time, the GPF required by a toilet has decreased from a startling 7 GPF to 3.5 GPF and then to 1.6 GPF. However, in recent years, there has been a demand for a GPF that is even lower. 1.28 GPF toilets have arrived and are gaining popularity in homes.

Keep in mind that the average person uses the restroom 4 to 7 times per day. So, according to the numbers, people used 49 gallons or more of water just to flush the toilet—and that’s just for one person!

To save water more effectively, toilet manufacturers went back to the drawing board to create toilets that used less water per flush. As a result, water-efficient toilets hit the market, offering up to a 70% reduction in water usage.

1.28 GPF Toilets: Overview

In essence, a 1.28 GPF toilet is the same as any other toilet you’ve ever used. Because all of the differences are internal, you’d never be able to tell the difference just by looking at it or using it. So, what’s the difference if it feels and looks the same? Why bother getting a 1.28 GPF toilet in the first place?

This version is efficient, requiring only 1.28 gallons per flush. It is considered environmentally friendly even in homes with multiple toilets because it ends the reign of high water consumption toilets. Furthermore, a single flush can efficiently clear the waste. You want it because it is a low-cost option that can help you save water.

1.6 GPF Toilets: Overview

If you live in the United States today, you’ve almost certainly used a 1.6 GPF toilet at some point, as these have been the standard since 1992. There is no discernible difference between a 1.6 GPF toilet and a 1.28 GPF toilet in terms of looks, appearance, or how you use it. However, the 1.6 GPF toilet uses significantly more water internally.

This toilet uses more water than the previous one but is still effective. It meets the federal government’s standards, but not all states accept it. You will not be disappointed because it does not have a weak flush. Heavy waste, on the other hand, can be disposed of in single flushing.

Furthermore, it easily removes the stain and does not usually clog. It is the polar opposite of dual flush toilets in that it only requires one flush to complete its function.

1.28 vs 1.6 GPF: Which Is the Best?

Toilets manufactured prior to 1980 used a whopping five to eight gallons per flush. Each person uses approximately 48 gallons of water per day just to go to the bathroom. But our current standard was established nearly two decades ago; surely there must be a more cost-effective solution by now, right? Yes, there are 1.28 GPF toilets. Let’s compare them to 1.6 GPF toilets to see if it’s an improvement or if 1.6 GPF is better.

Though the most noticeable difference between 1.28 GPF and 1.6 GPF toilets is the amount of water required to flush the toilet, there are other differences to consider when comparing these types of toilets.

And if you’re in the market for a new toilet, knowing more about these distinctions will help you decide which one is best for your home.

Power Flush vs Quiet Flush

The main distinction between the two is the flush power. Though both toilets use less water than their predecessors, the 1.6 GPF toilet has a slightly higher flush power. Furthermore, 1.6 GPF toilets have a larger flush valve, allowing more water to enter the toilet bowl, resulting in a stronger and more powerful flush. A higher flush power means the toilet is less likely to clog. This means that in situations where you may accidentally flush too much toilet paper, non-biodegradable items, or a large amount of waste to flush, a 1.6 GPF toilet will be better equipped to provide a powerful enough flush.

Fortunately, many 1.28 GPF toilet manufacturers have recognized this issue and are taking action. Several toilet manufacturers have released special power flushes designed to make the most of the limited amount of water. Another advantage of a low-volume flush is that it is quiet.

Water Efficiency

As you might expect, a 1.28 GPF toilet saves slightly more water per flush than a 1.6 GPF toilet. If you have a larger household or want to save as much money as possible on your water bill, the 1.28 toilet is a good choice. A 1.28 GPF toilet uses roughly one-third less water per flush than a standard 1.6 GPF toilet.

Assume you have three people in your house and each of them flushes the toilet six times per day on average. With a 1.2 GPF toilet, your total water consumption over a 30-day period will be 192 gallons. With 1.6 GPF toilets, your total water consumption over the same time period would be 240 gallons. A 1.28 GPF toilet could potentially save about 10 gallons of water per day in a three-person household. When you multiply that by a decade, you can see the true benefit of a low-flow toilet.

Cost Factor and Maintenance

Is price your primary concern? This may come as a surprise, but the average 1.28 GPF toilet is typically 10-20% more expensive than 1.6 GPF toilets. Why? Because it simply conserves more water and is thus more efficient.

Not only that, but some states offer a rebate if you buy a 1.28 GPF toilet, which helps them reduce water usage within the state. When it comes to long-term savings, the 1.28 GPF may still be the clear winner in this category. The toilet may cost a little more up front, but you’ll save money on water.

If you buy a 1.28 GPF toilet, you may find yourself dealing with clogged toilets more frequently due to their weaker flushing capability though some toilet brands are better than others. This problem is less common with 1.6 GPF toilets.

So, if you’re prone to clogs or leaving marks in the toilet after dropping off a few friends, you might want to consider 1.6 GPF toilets to reduce the amount of cleaning and maintenance you have to do on a daily basis.

Eco-Friendly Factor

Which option do you think is the most environmentally friendly? If you are concerned about this factor, the 1.28 GPF toilet is most likely the best choice for you.

The pressure to reduce the strain on natural resources such as water frequently results in local and federal governments enacting mandates to help protect the environment. And, believe it or not, you can help in a small way by purchasing a low-flow toilet. In terms of environmental friendliness, the 1.28 GPF always wins over the 1.6 GPF.

Pros and Cons of 1.28 GPF toilets


  • Uses about 1/3 less water per flush
  • Quiet Flush
  • Eco-friendly design
  • Saves water and money
  • In the United States, all states allow this model


  • Flush not powerful enough to evacuate massive waste
  • Often leaves skid marks
  • May require additional flush

Pros and Cons of 1.6 GPF toilets


  • Powerful flush for maximum effect
  • Less frequency to clean the toilet
  • Single flush is enough


  • Loud flush
  • Not eco-friendly
  • Wastes water
  • In the United States, many states ban the 1.6 GPF model

Best 1.28 GPF Toilet

Kohler K-3999-0 Highline Comfort Height Toilet

kohler highline

This elongated two-Piece toilet has a contemporary design and offers just one color option: white. The best part is the toilet is easy to clean and bacteria-resistant.

The Kohler Highline saves water by utilizing only 1.28 GPF. It packs a forceful punch and swiftly washes away all waste, so you don’t have to press it again. A comfortable plunger is included and can be pushed down to begin the flushing procedure.

Moreover, the bowl is elongated, making it suitable for both men and women of all ages and health concerns. Additionally, the toilet possesses comfort-height of a standard chair.

You have to order the seat and the supply line separately as these are not included in the pack, but all the bolts are included. And talking about the price, the cost of the Kohler Highline 1.28 GPF toilet ranges from $300 to $350.



  • No extra features are offered by the developer.

Best 1.6 GPF Toilet

TOTO Drake 2-Piece Ada Toilet with Elongated Bowl

TOTO CST744SL Drake 2-Piece Ada 1.6 GPF Toilet

TOTO CST744SL#01 Drake is a single flush elongated two-piece comfort height toilet. It is the best 1.6 GPF toilet in my opinion.

This comfort height toilet is ADA-compliant and possesses a height of 16.5 inches. This height is from the base of the toilet to the top of the toilet bowl, without a seat. Drake 2 comes without a toilet seat, so you have to buy it separately.

TOTO Drake 2 uses 1.6 gallons of water per flush. Hence it is not WaterSense certified. So, it can not be sold in places like California. This tall toilet uses Toto G-max flushing technology consisting of a large flush, an extra-large siphon jet, and a 2-1/8 inch fully glazed trap way. This drives a large amount of water into the toilet bowl very fast resulting in a powerful flush.

Moreover, these 1.6gpf toilets are designed so that they are powerful enough for both residential and commercial applications. Apart from this, an elongated toilet bowl would be a good option to match this comfort height toilet.

Meanwhile, this TOTO CST744SL#01 Drake comfort height toilet model comes with a 1-year warranty.


  • G-Max flushing system
  • Good choice for seniors
  • 1.6 GPF is effective for people with big stools
  • Fewest clog reports
  • Worth the money


  • Doesn’t come with a seat

What is a WaterSense Certified Toilet?

A WaterSense certified label guarantees a high-quality toilet that has undergone rigorous testing to ensure that it performs to a high standard while also being extremely water efficient. In fact, a toilet must use less than 1.6 GPF to be WaterSense Certified. The Environmental Protection Agency (EPA) has independently tested and certified these toilets.

They are commonly found in residential homes, but due to their superior overall performance, they are becoming more popular in commercial settings as well.

Dual Flush Toilets: 1.28 and 1.6 GPF Toilets Alternative

You’re not alone if you’re wondering how to get the best of both worlds with a toilet that can save water while also having enough pushing power. And, more importantly, there is a choice. It’s known as a dual flush toilet.

These versatile low flush toilets are making their mark in the industry by providing flushing options of 1.28 and 1.6 GPF. Dual flush toilets allow you to use a half flush or a full flush. You can use a half flush for liquid waste, which can be as low as 0.8 GPF. A full flush can be used for solid waste. A complete flush can be as low as 1.28 GPF.

Simply use the lighter flush option for liquid waste and the heavy flush option for solid waste. The majority of dual flush toilets are also WaterSense certified, which is a plus.

Furthermore, when compared to 1.28 GPF and 1.6 GPF single flush toilets, dual flush toilets have a lower overall water consumption rate. This is due in part to half flushes replacing full flushes for liquid waste, but it also uses less water per flush on average.

Frequently Asked Questions (FAQs)

What toilet flush capacity do plumbers recommend?

Toilets with 1.28 GPF are already as good as those with 1.6 GPF. In any case, it is dependent on the specific model you select, as well as its design, bowl coverage, dual flush, and your water system and drainpipes in general.

If it performs worse than expected, you can add a pressure-assist module. If you don’t want to take chances, there are plenty of 1.6 GPF models to choose from.

Can You Buy 1.6 GPF Toilets in Texas or California?

As previously stated, not all states permit the use of 1.6 GPF toilets. Texas and California, for example, are two states that prohibit the use of this type of toilet.

Toilet water accounts for more than 30 percent of all indoor water usage in the United States. High water wastage is a major concern in drought-prone states like California and Texas. California was the first to implement this rule, and Texas quickly followed suit. It became a method of conserving water and, in the long run, aided states in becoming more environmentally conscious.

How Much Water is Wasted When Using 1.6 GPF Toilets?

A single person using a 1.6 GPF toilet could waste about two gallons of water per day. Because 1.6 GPF toilets require more water when flushing, it not only raises your water bill, but is also a waste of precious natural resources. However, due to the low water volume of 1.28 GPF, the toilet sometimes must be flushed twice.

What flush capacity is best for not clogging?

Larger loads, especially when dealing with solid waste, aren’t always washed down with a 1.28 GPF toilet. Because of the limited amount of water used in a flush, skid marks appear to be a common occurrence. A 1.6 GPF toilet, however, may use more water but reduces the chances of clogging altogether.

1.28 vs 1.6 GPF Toilets: WINNER

So, who wins the 1.28 vs. 1.6 GPF fight? If you have a larger household and want to save more water than someone who lives alone, a 1.28 may be a better choice. If flushing power is critical to you and you don’t use a lot of water on a regular basis, the 1.6 may be a better fit. Of course, if you’re still undecided, there’s always the dual-flush option.

In the end, the difference between a 1.28 GPF toilet and a 1.6 GPF toilet is negligible. While it can add up over time, a more conservative toilet may actually waste more water if you have to flush it twice or clean it more frequently than another toilet.

If you have a large family, you may save more water than a single person living alone, so the savings on your water bill may be enough to justify the switch. Similarly, if you’re extremely concerned about your environmental impact, choose the 1.28 GPF toilet.

However, if you don’t mind spending time cleaning skid marks from your toilet bowl and don’t mind a louder flush, you might consider a 1.6 GPF toilet.

Leave a Comment