5 Awesome KOHLER San Souci Toilet Models

KOHLER San Souci Toilet Review

KOHLER San Souci Toilet Review

Which KOHLER San Souci Toilet Model Is Right For You?

There are probably a gazillion one piece toilet models out there, and you just have to go for a KOHLER San Souci toilet.

Well, it’s not hard to understand why especially when you have adopted a modern or contemporary bathroom design. This KOHLER one piece crapper aims to appeal to those who want to break away from the boring ‘tank and bowl’ look of a toilet, and yet still prefers a tank and bowl toilet for their bathroom.

Sure, there is always the super looker tankless or wall hung variety. It’s a different feel (read expensive), can’t compare. Besides, it’s a KOHLER toilet. It is reliable, good quality and you’ve always wanted a piece of KOHLER in the house.

Yeah sure.

So, what exactly is in the appearance that makes this KOHLER San Souci one-piece toilet stands out among the competition? And more so, attracted you?

There is this little design edge (appearance wise) of this San Souci toilet that is so irresistible you can hardly get away with, especially if you are an impulsive shopper. But that’s not your fault because even the bathroom designers find it hard to resist.

Regardless, this KOHLER San Souci toilet review is going to pry open the good, the bad and the “ugly” side of this KOHLER one-piece toilet. All to treat your helpless impulsiveness and help you make an informed purchase.

Comparable to KOHLER Santa Rosa But…

San Souci vs Santa Rosa

If you have been looking for a one-piece toilet, then the KOHLER Santa Rosa toilet is no stranger. You probably have seen it on Amazon, Lowes, Home Depot, and many other popular online stores with good reviews.

While this KOHLER San Souci toilet is also available at these online retailers, reviews are scarce and not as highly rated. And if that leads you to think it probably doesn’t perform as good as the Santa Rosa, that would be grossly misleading.

The fact is, the performing specifications are rather similar with the well reviewed Santa Rosa water closet.

The only difference is, of course, the appearance. And like it or not, the San Souci is a much better-looking toilet and nowhere inferior in performance.

Let’s have a look at what the similarities are between Santa Rosa and San Souci;

KOHLER San Souci Vs Santa Rosa Toilet

DescriptionSan Souci
Santa Rosa
Toilet typeOne-piece, Floor-mountOne-piece, Floor-mount
Bowl shapeElongated frontElongated
Flush typeAquaPistonAquaPiston
Trap passageway2-1/8″ (54 mm)2-1/8″ (54 mm)
Water Consumption
(Full flush)
1.28 gpf (4.8 lpf)1.28 gpf (4.8 lpf)
Water surface size10-3/4″ x 7-1/2″
(273mm x 191mm)
11″ x 8-1/8″
(279mm x 206mm)
Rough-in12″ (305mm)12″ (305mm)
Overall length27-1/2″ (699mm)27-3/4″ (705mm)
Overall height25-5/16″ (643mm)28-3/16″ (716mm)
Bowl width14-3/8″ (366mm)14-3/4″ (375mm)
Bowl height16-1/2″ (419mm)16-1/2″ (419mm)

*The Odd One Out…
Except for San Souci K-4007, which is a regular height toilet with a round front bowl, the rest of the models are similar in size and shape.

As you can see there really isn’t a huge contrast in the specifications.

The overall height has no bearing on the flushing performance. But the bowl height and length can affect the trapway bend and diameter which in turn affects the siphon power. And since the bowl dimensions of both toilets are almost similar, there should be no significant difference in flushing power and efficiency.

A 1/4″ and 3/8″ difference in overall length and bowl width respectively will have no impact on the flushing performance at all.

So does that mean what works for the Santa Rosa model, the San Souci toilet should yield similar performance level as well?

Well, not quite. But close.

It depends on the flush valve which apparently is different in construction even though both are using the AquaPiston flushing systems. Let’s discuss more on the AquaPiston flush valve for this San Souci toilet later, and why it is not as powerful as the Santa Rosa.

But wait. Why compare this KOHLER San Souci toilet with only the Santa Rosa model?

How about matching up with the Cimarron? Cimarron is another of KOHLER’s best selling toilet.

Fair enough and there are two reasons why Cimarron will not make a good comparison model.

  1. The Santa Rosa model is the closest in size with the San Souci toilet. And they are both classified as compact toilets with a length of a little over 27 inches.
  2. Whereas the Cimarron has a length of over 29 inches, which is considered more of a regular size toilet. Besides, the Cimarron model that is selling well is a two-piece toilet.

The Cimarron one-piece model has the same fate as this San Souci toilet; both are not getting the reviews. You will find out why in a while. But for now, let’s get on with the features of this sexy San Souci toilette.

The Good – Great Features To Accomodate Your Preference

San Souci Features

Steve Martin didn't whatWant it tall or short, touch or touchless, round or oval, left or right, there will always be one model that will meet your requirement.

Well, unless you want it to be made of wood.

And with ten color choices to choose from, it’s impossible not to find one to match your modern bathroom decor. You will have no excuses to say “Yeah I like this San Souci toilet, but it didn’t…..”

Knee-Friendly Tall Bowl

Comfort Height ADA CompliantIf you love a tall bowl toilet, then you will love this KOHLER San Souci toilet. Besides looking sexy in your designer bathroom, you will find sitting down and getting up from the seat a breeze.

All the San Souci models, except K-4007, have a 16-1/2″ high bowl. These are the comfort height models which meet the ADA standards for accessible design.

The advantage of having a comfort height toilet has been mentioned a few thousand times on this website. So not going to bore you with another rehash. Search for it please if you have to know.

And as usual, not everyone loves a tall toilet. In fact, the comfort height offers no comfort at all to these folks. So if you are unfazed by the comfort hype, there is always the K-4007 model. The only model in this San Souci series that goes with a regular seat height and a round-front bowl.

Life is Short Don’t Waste it on the Trapways

San Souci Model K-4007
San Souci Model K-4007 – Can you see the trapway?

If you can’t hide the dirt, at least make it easy for yourself to wipe them off. That’s what the concealed trapway design is for and can really make toilet cleaning a lot less of a chore.

You will love this feature as it can only mean less cleaning and more time to watch cat videos.

The only model that has its trapway exposed is K-4007. So bear in mind, if you prefer a regular height or a round-front San Souci toilet, then you’ve got to go with this least expensive model with exposed trapway.

Powerful AquaPiston Flushing System

The AquaPiston flush valve used in this San Souci toilet is a different one from Santa Rosa. The canister flush valve, in this case, has a shorter body. Apparently, this is to accommodate the low profile tank design.

Different AquaPiston Assembly

And this has an advantage over the taller (regular size) AquaPiston canister flush valve – it requires lighter actuation force to pull a flush. But the drawback is, your two-year-old may find toilet flushing fun when the trip lever is so easy to pull.

Alright jokes aside, the flush power is a tad weak compared to the Santa Rosa. It is mainly due to the low profile tank and not the fault of the AquaPiston flush valve.

If you have to ask why, well, that has a lot to do with flow physics. It’s common knowledge to the engineers but never easy to explain without boring you to death.

Just remember this;

Water pressure increases proportionally to the depth of the water. The deeper the water is, the more weight (of water) exerts on the water at the bottom. Therefore, a taller tank will have higher water pressure at the valve opening than a shallow tank holding the same amount of water.

And that can only mean the taller tank of the Santa Rosa toilet will have the advantage of a higher water flow speed. Since both toilets have almost similar bowl design, the Santa Rosa will give a slightly stronger flush than the San Souci toilet.

But that does not mean the San Souci is a pushover. Despite its low tank profile, it is still able to pull a powerful flush. So it is far from being just a piece of pretty looking furniture in the bathroom.

Here’s proof of its flushing power (MaP rating comparison).
MaP rating Comparison
Comparison Table from map-testing.com

As you can see the San Souci still packs an impressive 800 on the MaP Flush Score, which is within the ‘Highly Recommended’ category for Great Flushing Performance.

MaP Scoring Guide

And one distinct advantage of the AquaPiston flush valve is having 90% less exposed seal material than the usual flapper valve. This canister valve design eliminates the possibility of leaks. And through the years, KOHLER has been improving its AquaPiston valves for better performance and to be leak-free.

Space Saving Without The Squeeze

The general consensus of a compact toilet is that the length should not be more than 28 inches. And the length is the most critical dimension when you are plotting for the minimum space for a toilet.

So at 14 inches wide (bowl width) and 27-1/2 inches long, this San Souci porcelain throne will fit in any small bathroom layout* without the awkwardness.

And the round bowl K-4007 model will save you a further 2 inches at 25-5/8″ (front to back). Any smaller than this, you will have to look elsewhere such as this 24-inch toilet (possibly the smallest floor-mounted siphonic toilet in the USA).

*Subject to the Minimum Space Requirement.

Toilet Length
SAN SOUCI – Total Length of Elongated Bowl and Round Front Bowl Toilet

Dealing with a Really Small Bathroom?
Then check out these small toilets for more options.

The Choice Of Manual Or Touchless Flush And Purefresh

This KOHLER San Souci toilet has five different models altogether. Out of the five models, two are touchless-flush which uses a tank sensor to facilitate flushing.

The sensor unit is powered by 4 numbers of AA size batteries (included) and mechanically connected to the AquaPiston flush valve. So the two touchless flush models do not have the trip lever. And no handle means contamination through touch is minimized or eliminated.

This touchless flush feature is perfect for big families who share a common bathroom, or as a guest toilet.

KOHLER San Souci Touchless Flush Toilets

Here are the only two models with the touchless flush mechanism. (Psst…..actually they are the same toilet)

And now you wonder what’s the difference between the two touchless flush San Souci crapper.

Answer: The toilet seat. (duh)

Sorry if you feel that your intelligence has been humiliated, that’s how ‘creative’ marketing works (at its worst). But what’s even worse is the price difference if you buy the seat separately versus if you buy the K-8687 (DISCONTINUED), the model with the Purfresh seat.

So if you need the Purefresh seat badly, just buy the K-4000 model (DISCONTINUED) and the K-5588 Purefresh seat separately. You can save some money this way, and you have two seats instead of one (versus if you buy just the K-8687 (DISCONTINUED) San Souci model).

AND, the K-8687 (DISCONTINUED) offers only 2 color choices versus 10 for K-4000. So why limit yourself. (Seriously, what were they thinking?)

What is Purefresh?

According to KOHLER…

Purefresh combines a carbon deodorizing system that neutralizes odors and a built-in freshener that releases a light scent. This battery-operated seat also includes Nightlight illumination so you can safely locate your toilet in the dark. Unique Grip-Tight bumpers hold the seat firmly in place and prevent shifting. This slow-close seat features technology that prevents the seat from slamming and simplifies both cleaning and installation. – KOHLER

The question is, do you need the Purefresh seat?

Maybe it’s good to have if you have a small bathroom, and ventilation is less than ideal. Always good to keep the bathroom fresh and smelling good…well, at least make it odorless for the next user.

KOHLER K-5588 Purefresh Seat

Manual Flush Models

So you prefer the good old fashion trip lever activation? Nothing wrong with that. In fact, it does have some advantages over the touchless flush.

At the very least, you don’t have to deal with the troublesomeness associated with flat batteries. And you save money too. Plus there is no such thing as the ghostly flushing like the folks are experiencing with the touchless flush.

So here you go, the three trip-lever flushing models and their differences.

The Differences Among The 3 Trip Lever Flush Models

KOHLER K-4007-0, the only model that is a regular seat height toilet with a round front bowl and its trapway is not concealed. The overall length is 2 inches shorter than the rest of the San Souci models. Perfect for a small bathroom with limited front to back spaces.

If you just want a comfort height toilet with an elongated bowl, left or right-hand trip lever and concealed trapway, then the KOHLER K-5172 is the right model to pick. The difference between the K-5172-0 and K-5172-RA-0 is the location of the trip lever.

K-5172-0 trip lever is on the left, whereas K-5172-RA-0 is on the right.

BUT, if you choose the right-hand lever K-5172-RA model, you are limited to only 3 color options. Whereas the KOHLER K-5172 offers 10 color options to match your prized bathroom decor.

Backbreaking Installation

Backbreaking is when you are doing the installation all alone by yourself. And it is not recommended for safety sake. You should either do the installation with some helping hands or hire the expert.

This handsome boy may be small, but it weighs over 90 lbs in one big piece of fragile porcelain. So there’s no way you can separate the mass and weight when lifting to position over the flange.

And the toilet is most vulnerable to breakage during installation. So tread carefully, don’t rush and observe safety throughout the installation. In no time you will have this art piece sitting pretty in your bathroom.

Remember, this is a one piece toilet. There is no room for error that leads to cracks or chip-offs rendering the water closet unsafe or unusable.

Failed toilet installation

But still, it is easy to install this KOHLER San Souci toilet. Once you got it in position, the rest is just a casual stroll in the park. Unlike most concealed trapway toilets where the mounting bolts are hidden, this San Souci toilet have them accessible just like any exposed trapway toilets.

Accessible Mounting

It’s a standard toilet installation. There are no special procedures or mounting materials and tools needed. Any competent plumber will be able to breeze through the entire installation.

The Bad – It’s Not That Bad After All

The main disadvantage with all one piece toilet is the porcelain or ceramic. Except for the tank lid, if you broke any part of the toilet tank or bowl you have to replace the whole toilet. So this KOHLER San Souci one piece toilet is no different.

But of course, you are more interested in the problems that are unique to this San Souci toilet. What are they then?

Is The Touchless Flush A Disaster? [This Feature is no longer available]

You may have read or heard about those eerie phantom flushes that come about in the middle of the night. Or you may have experienced it yourself. At that time you were dead sure there wasn’t anyone using the toilet because you were all alone in the house. Then suddenly …..

Alright, this is no horror story. You are reading a KOHLER San Souci toilet review, remember?

And yes this San Souci touchless flush toilet can replicate one of those water and money wasting ghost flushes. What’s scary about it is its ability to make the replication all by itself without human intervention.

So unless you take the necessary steps to stop it, one of these nights when you are least expected….At exactly midnight, the toilet in the bathroom flushes and followed by the door creaking open….

OK, the creaking door part was made up. Anyway, there’s always WD40 to kill the creak. And if you think you can’t afford the risk of a phantom flush even after taking the precautionary steps to stop it, there’s always the manual trip lever flush models.

Limited Color Choice For This 2 Models

UPDATE 2023: The new San Souci has 6 color options and K-8687 & K-4000 are discontinued.

When White, or near White is all you need, you may skip to the next section. Otherwise please take note of these two models, K-5172-RA, and K-8687 (DISCONTINUED).

K-5172-RA has only three color options: White, Biscuit, and Almond.
K-8687 (DISCONTINUED) has just two colors: White and Biscuit.

In the case of K-5172-RA, it’s understandable since the right-hand handle is not as common as having the trip lever on the left. If you look at TOTO or American Standard, you will notice all their trip-lever flush toilets are by default left-handed. So kudos to KOHLER for providing a right-hand option for this San Souci water closet. Though it offers limited color options, it provides a solution to those who may need it.

But for K-8687 (DISCONTINUED), you should check and compare the price difference between buying just the K-8687 model (DISCONTINUED) alone or a combination of San Souci K-4000 and the Purefresh K-5588 seat. In any case, the Purefresh seat also comes in White and Biscuit only.

Not A Fan Of Comfort Height? You Don’t Deserve These Features Then.

Why isn’t an elongated bowl model be made available with regular bowl height? And why can’t they make the K-4007 with a concealed trapway like those comfort height models?

Don’t you hate it when the features you want aren’t available on the only model that suits you? So are you going to bend a little and go for a comfort height model? It looks like you don’t have much choice if that unique San Souci look is a must-have in your bathroom.

Go scream at KOHLER?

Na. Don’t do that. There are plenty of other options out there. KOHLER is just one of the better toilet manufacturers on planet earth.

The Killer Looks

KOHLER San Souci Toilet With Bidet Seat
Image from www.us.kohler.com
Alright, admit it. It’s the appearance of this San Souci toilet that got you here to find out if this pretty boy is just a pretty boy. And judging from the specification, it is quite a mean flushing machine beneath its elegant exterior. Though its flushing power is not as badass as the Santa Rosa model, it still offers decent flushing power and rinsing efficiency.

So, what is so unique about the appearance?

It doesn’t have that typical tank and bowl toilet look despite being one.

The low tank profile is almost an emulation of the tankless toilet, especially when you fit it with a smart bidet seat, such as the KOHLER C3®-230 (as seen in the picture above).

The overall aesthetics stamp from the smooth and curvy integrating surface of the tank base and the bowl, and the broad front bowl base provides an embracing feel both visually and in touch.

San Souci Aesthetics

It is every designer’s favorite inclusion in their modern bathroom designs. And if you don’t have the budget for a wall hung system or the intelligent tankless toilet, do consider this KOHLER San Souci toilet. It is so much easier on the wallet, and there is no compromise on aesthetics and function at all.

Which Model Is Right For You?

All modelsStandard Features
  1. AquaPiston flushing system
  2. Trapway size 2-1/8″
  3. Water consumption 1.28 gpf (4.8 lpf)
  4. Rough-in 12″ (305mm)
  5. WaterSense labeled
KOHLER K-4007-0 San Souci
Model: K-4007
  1. Standard Features
  2. Round-front bowl
  3. Trip lever activation (left)
  4. Exposed trapway
  5. Water surface area 9-1/4″ x 6-3/4″ (235mm x 171mm)
  6. Toilet length 25-5/8″ (651mm)
  7. Toilet height 24-1/4″ (616mm)
  8. Bowl width ~14-5/16″ (364mm)
  9. Bowl height 15-1/4″
  10. 10 color options
KOHLER K-5172-0 San Souci Comfort Height
Model: K-5172-0
  1. Standard Features
  2. Elongated bowl
  3. Trip lever activation (left)
  4. Concealed trapway
  5. Water surface area 10-3/4″ x 7-1/2″ (273mm x 191mm)
  6. Toilet length 27-1/2″ (699mm)
  7. Toilet height 25-5/16″ (643mm)
  8. Bowl width ~14-1/4″ (362mm)
  9. Bowl height 16-1/2″(419mm)
  10. Comfort height
  11. ADA compliant
  12. 10 color options
KOHLER K-5172-RA San Souci Comfort Height
Model: K-5172-RA
  1. Standard Features
  2. Elongated bowl
  3. Trip lever activation (right)
  4. Concealed trapway
  5. Water surface area 10-3/4″ x 7-1/2″ (273mm x 191mm)
  6. Toilet length 27-1/2″ (699mm)
  7. Toilet height 25-5/16″ (643mm)
  8. Bowl width ~14-1/4″ (362mm)
  9. Bowl height 16-1/2″ (419mm)
  10. Comfort height
  11. ADA compliant
  12. 3 color options
KOHLER K-4000 San Souci Comfort Height Touchless Flush
Model: K-4000-0


  1. Standard Features
  2. Elongated bowl
  3. Touchless activation
  4. Concealed trapway
  5. Water surface area 10-3/4″ x 7-1/2″ (273mm x 191mm)
  6. Toilet length 27-1/2″ (699mm)
  7. Toilet height 25-5/16″ (643mm)
  8. Bowl width ~14-3/16″ (360mm)
  9. Bowl height 16-1/2″ (419mm)
  10. Comfort height
  11. ADA compliant
  12. 10 color options
KOHLER K-8687 San Souci Comfort Height Touchless Flush with Purefresh Seat
Model: K-8687-0


  1. Standard Features
  2. Elongated bowl
  3. Touchless activation
  4. Concealed trapway
  5. Water surface area 10-3/4″ x 7-1/2″ (273mm x 191mm)
  6. Toilet length 27-1/2″ (699mm)
  7. Toilet height 25-5/16″ (643mm)
  8. Bowl width ~14-3/16″ (360mm)
  9. Bowl height 16-1/2″ (419mm)
  10. Comfort height
  11. ADA compliant
  12. Purefresh seat
  13. 2 color options

Customers Are Not Giving Their Reviews

If you have been to Amazon and noticed the dismal state of customer reviews on this KOHLER San Souci toilet, rest assured, that’s no surprise at all.

Why is that so?

Though there aren’t any hard evidence to back up, it seems the price has an effect on the number of reviews. Any product that is priced above $500, reviews are usually scarce. Of course, there are exceptions, but generally, this is the case.

So based on this logic, you can extrapolate how the Santa Rosa model is getting far more reviews than this San Souci one piece toilet.

And as you have seen the comparison of this two models above, their specifications are rather similar. It just doesn’t add up that one is being raved about while the other is getting the cold treatment. So the only conclusion you can draw is perhaps, the higher price San Souci gets fewer buyers, hence the lesser number of reviews than the lower price Santa Rosa toilet.

So take those reviews, or the lack of it, with a ton of salt. They don’t always reflect the product quality and performance accurately.

And you should have noticed, most of the negative comments are about the touchless flush which is either not flushing or erratic flushing on its own. The solution to the phantom flushing is in the video above.

Finally …

Have you decided? Or at least acknowledge that this KOHLER San Souci toilet is not too bad after all? Or it could be the price that turns you off more than the build and performance?

Whatever. That’s your decision and your call at the end of the day.

And just in case you decide to pick up the touchless flush model, please remember to do the precautionary step of preventing the hated phantom flushing. Otherwise, the trip lever model is just as awesome if you don’t mind the regular cleaning to keep the handle free of germs and bacteria.

Don’t like a tall toilet?

Well, unless you wouldn’t mind that the only regular height model, K-4007, is a round front bowl and with its trapway exposed. And cleaning will not be as easy as the concealed trapway model.

Anyway, the difference between the comfort height and the regular height model is only one and a quarter inch (1-1/4″). With that difference do you think you will find any discomfort with the comfort height model? Can you use the Squatty Potty if other members of the family insist on a comfort height toilet?

Of course, you don’t have to agree with everything you have read here. And you may have a ton of questions that need answers. Why not leave a comment below, let’s discuss and make this KOHLER San Souci toilet review the de facto go-to forum for all things San Souci (the toilet of course).

San Souci Design

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