Kohler Highline Arc Vs Highline Curve: Detailed Comparison

Written by

Paulk Webb


Freddie J. Hagopian

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kohler highline arc vs highline curve

There are various toilets that you can choose from Kohler since it’s one of the reputable toilet makers. When going over different models, you may scratch your head when looking at Kohler Highline Arc vs Highline Curve. It’s normal to be confused since they look similar in photos and by looking at them quickly.

If you haven’t noticed, Highline Arc has an elongated seat while the Highline Curve has a round seat. When looking at the product description, the confusion gets worse as they work with the same flushing system. They also both operate with 1.28 GPF.

Since I could use two of these toilet models, I’ll share my experiences and observations. I was able to talk to some people who have these toilets in forums too. Continue reading as I’ll reveal everything I know. These pieces of information will help you to pick the suitable one for you.

Things to Expect From Kohler Highline Toilets

1. Material and design


The body of Highline toilets is made of vitreous China, so no wonder why they look awesome. Some have an elongated bowl while other models have round. The elongated bowl is more favorable since it can offer more sitting space. It brings convenience and comfort.

They are available in one-piece or two-piece. However, the former will make cleaning much easier. Leakage is a common issue among the usual two-piece toilets but Kohler has put an end to this. It’s done by improving installation designs and flushing systems.

2. Seat height

Highline toilets are ADA compliant because adults of different ages and conditions can use them. They’re two inches higher than the regular toilet. You can compare it with a kitchen chair.

Kohler Highline Arc


Many users testified that the Kohler Highline Arc toilet is life-changing in terms of comfort, performance, and installation. It’s a WaterSense toilet that complies with EPA flushing guidelines. Moreover, you don’t need to head to the hardware store for some components as you can get this in a complete set. The following part will discuss why this toilet makes a difference in the life of the users.

1. Comfort

You can say goodbye to your old, leg-numbing toilet because this toilet has a comfortable height similar to a standard chair. It measures 15 5/8 inches from the floor and it has a 12-inch rough-in. It can be higher if you add the thickness of the toilet seat. Therefore, people of different heights can be comfortable with it.

It’s neither too tall nor too short. Even the elderly and people with disabilities find it manageable to use it. With its elongated seat, there’s more room for comfort when you sit on it.

2. Powerful flush for cleanliness


The single flush with 1.28 GPF is awesome as it becomes powerful with its Class Five flushing technology. You’ll surely be in awe of its ability to flush bulk waste. The waste just goes down the sewer without hang-ups because its valve functions with a powerful punch. Even though powerful, the flushing occurs quickly. You can accomplish this without needing to do another flush. 1.28 gallons is sufficient to get rid of the waste.

At this point, you figure out that you can save water and easily keep the toilet clean. A bit of waste or particles won’t stick on the bowl so cleaning every after use is not necessary all the time. This toilet is made of vitreous china, a material that can be maintained with ease.

3. Installation

It’s common to see some people get confused with installation because the hardware is not available upon purchase. This won’t be a problem when you receive Kohler Highline Arc toilet k-78279-0 because it includes a wax ring and floor hardware.

As per the process, the assembling is straightforward. Its three-bolt system is awesome since the tank is attached to the base securely. The whole body is steady and sturdy without rocking.

4. The downside of highline Arc

I haven’t come across serious issues with this toilet. As long as you clean it regularly, it won’t cease functioning properly. Here are a few things that may bother you momentarily.

  • Some may have an impression that the flush doesn’t work properly. What I discovered is that the chain can be too long. I was clever enough to move the clip on the chain through six links. It’s a simple solution that you can do without pressure.

Kohler Highline Curve


Kohler Highline Curve toilet is the best choice for powder rooms and bathrooms with limited space. It’s due to its round seat, which doesn’t occupy space as much as the elongated one. It’s also a 1.28 GPF WaterSense that meets the criteria of EPA. Apart from being a space saver, special features make this toilet stand out. They’re the comfort height, slow-close seat, DryLock, and flushing performance.

1. Comfort height

Just like Highline Arc, this has a comfort height of 17 inches with its slow-close seat. With the additional two inches from a regular toilet, most adults easily use this toilet. Standing and sitting whenever responding to the call of nature is not bothersome.

2. Slow-close seat

There’s no need to be conscious when you prefer to cover the toilet if there’s a slow-close seat. It’s an advantage as it won’t create noise that may bother other people, especially at night.

3. Installation and DryLock

A single purchase comes as a complete bowl, tank, hardware, and wax ring package. You can do the installation right away without going to the store for missing parts. The three-bolt system makes it so easy to install for the right placement of the toilet. DryLock tank feature that has insuliner contributes a lot in this aspect. This is also great for condensation of the outer surface when humidity is present

4. Cons of Highline Curve

There are no cons that can be disturbing to the users. Some are more comfortable sitting on a toilet with an elongated seat. Since this has a round seat, it can’t please everyone.

Comparison of Highline Arc and Highline Curve

Here are the dimensions and features that you’re interested in.

Features Highline Arc Highline Curve
Bowl shape Elongated Round
Dimensions 29.5” x 18” x 31.25” ‎27.75” x 18.19” x 31.25”
Height Comfort height Comfort height
Rough-in 12” 12”
Certification WaterSense WaterSense
Material Vitreous china Vitreous china
Water consumption 1.28 GPF 1.28 GPF
Flush system Class 5 Class 5
Type Two-piece Two-piece


  • Comfort height

The height of the regular toilet is 15 inches, but both of them have 17 inches or more.

  • Class five flushing technology

Both of them have a flush valve that delivers a punch for a strong water surge, so waste disposal is great. With this strength, you can save water as a single flush is enough.

  • Water saver

They’re both water savers with 1.28 gallons for every flush. Each flush efficiently eliminates even the bulk of the waste, so you won’t need to do another flush. This means that you don’t have to clean readily after use. Vitreous china is also helpful in keeping the toilet clean with less effort.

  • Easy installation

The three-bolt design found in these toilets allows you to connect the tank and bowl easily. The whole toilet becomes sturdy and well-established. Not to mention that the hardware and wax ring is included for easy installation.

  • Other features

Both of them are two-piece toilets with a polished chrome trip lever on the left side. They have the same 12-inch rough-in too.

Are There Differences Between Highline Arc and Highline Curve?

The previous part shows that several features are shared by these toilets from Kohler. You might think that they’re almost identical. But there’s no use naming them differently if there’s no distinction. First, Highline Arc has an elongated seat, while Highline Curve has a round shape. Hence, you can expect more room for sitting from the former.

The seat’s shape also makes Highline Curve a space saver so it’s recommended for powder rooms and small bathrooms. Second, this toilet has a Drylock feature on its tank to minimize condensation when humidity rises. In addition, it has a slow-close seat so it won’t make much noise.

As you can see, there’s not much difference. It’s just about the shape of the seat. Also, Highline Curves is not only available in white color but biscuit as well.

Words to Ponder

There’s not much difference when comparing Kohler Highline Arc vs Highline Curve. I think Kohler just wants the buyers to easily distinguish which one has an elongated seat represented by ‘arc’ and the round seat for ‘curve’. They both have the same appearance, components, design, function, and performance. It’s just that the Highline Curve can prevent condensation when in a humid area.

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