TOTO S300e vs S500e: Which Washlet Should You Actually Buy?

If you’ve made it to this article, congratulations — you’re already thinking about your bathroom hygiene more seriously than most people ever will.

And you’ve landed on a genuinely interesting comparison.

The TOTO S300e and S500e are two of the most talked-about Washlet bidet seats on the market — beloved by urologists, caregivers, and people who simply refuse to go back to toilet paper once they’ve crossed that line. On the surface, they look nearly identical. Same price range. Same core features. Same “why didn’t I do this sooner” experience once installed.

But dig a little deeper — which I did, so you don’t have to — and the differences start to matter.

The S500e comes in four versions. The S300e in two. One supports AutoFlush. One offers a Contemporary lid design. Neither fits a round toilet. And somewhere in all of that, is the right answer for your bathroom.

Let’s find it.

If you have a round toilet, check out the TOTO S350e Washlet (Affiliate link). 

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TOTO S300e vs S500e: Quick Summary Table 

Feature(s)	TOTO S300e	TOTO S500e
Endless Warm Water (Tankless Heater)	Y	Y
Bowl Shape	Elongated and Round	Elongated Only
Warm Air Dryer	5 Temp Settings	5 Temp Settings
Heated Seat	5 Temp Settings	5 Temp Settings
Self-Cleaning Nozzle	Automatic	Automatic
Self-Sanitizing Nozzle	Ewater+	Ewater+
Wand Positions	5	5
Wand Material	Plastic	Plastic
Wireless Remote w/Wall-Mounted Cradle	Y	Y
Night Light	N	N
Auto Flush Compatible	N	Only with SKU’s SW3044AT40 and SW3046AT40
PREMIST of Bowl Before Use	Y	Y
Self-Cleaning Bowl (After-Mist)	Y	Y
Nozzle Oscillation	Y	Y
Nozzle Pulse/Massage	Y	Y
Personal Settings	2 User Presets	2 User Presets
Air Deodorizer	Y	Y
Energy Saver Functions	3 Eco Modes	4 Eco Modes
Water Temp	86 to 104 °F	86 to 104 °F
Water Pressure	0.07-0.11 gal/min or 0.27-0.43 L/min	0.08-0.11 gal/min or 0.32-0.43 L/min
Nozzle	Single, Plastic	Single, Plastic
Aesthetics	Classic Design Only	Classic and Contemporary Designs
Bulkiness (Rear Height)	3.84″ or 9.75cm	Classic: 5.04″ or 12.8cm Contemporary: 4.92″ or 12.5cm

The TOTO Washlet S500e – Classic

First up is the TOTO S500e Classic on Amazon and at BidetKing.

Pros:

• EWATER+ self-sanitizing technology is genuinely in a class of its own
• Tankless water heater means warm water never runs out — ever
• Ultra-slim design looks sleek enough to make your toilet look like it was imported

Cons:

• T-adapter installation leak is a known quirk that needs a hardware store pit stop
• The remote isn’t backlit — a mildly baffling oversight for a $900 product
• Seat opening runs slightly narrow for larger users

The TOTO Washlet S500e – Contemporary

Next, is the TOTO S500e Contemporary (also available on Amazon).

Pros:

• Same features of the S500e Classic.
• More of modern, minimalist look than the S500e Classic without a noticeable increase in price.
• Easy to find.

Cons:

• Around the same price as the S550e despite offering a fewer features.
• Only available for elongated toilets.

The TOTO Washlet S300e

Thirdly, is the TOTO S300e Washlet (Amazon).

Pros:

• Offers the most important features of the TOTO luxury bidtes.
• One of only two luxury TOTO bidets that are available for round and elongated toilets.

Cons:

• Harder to find and thus equally if not more expensive than the S500e and S550e bidets.
• Despite the cost, it’s only available in Classic and offers fewer features compared to other TOTO luxury seats.
• Only available in the Classic design.
• The more sophisticated S350e can be found for about the same price.

Sure, the S300e is still a TOTO luxury bidet, so it’s still one of the best and most sophisticated bidets on the market.

But in the end, I’d only recommend the S300e in the event that the S500e and S550e bidets were sold out for whatever reason, which isn’t likely.

The Main Differences 

The S300e Is Available in Round

This is the most significant difference, IMO, because having a round toilet completely rules out the S500e and S550e.

Luxury bidets for round toilets are less common because they’re designed with ultra-modern bathrooms in mind, which tend to be larger in size with elongated toilets.

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The Key Features – What TOTO S500e Claims to Offer

1. EWATER+ and PREMIST: The Hygiene Double Act

TOTO’s EWATER+ is the S500e’s headline party trick. The seat electrolyzes ordinary tap water into a mild but effective sanitizing compound. No chemicals. No additives. Just water — transformed.

Before you sit down, PREMIST sprays the bowl with a fine water mist. Its job? Prevent waste from sticking to the surface before you even get started. After you’re done, EWATER+ mists both the wand and the bowl. Everything gets sanitized — automatically.

The practical upshot? Your toilet bowl stays meaningfully cleaner between scrubs. And the wand is self-sanitized before and after every single use.

No other brand at this price point does this with electrolyzed water. Most competitors use UV light or silver-ion coatings. Those are fine. But they’re not quite the same engineering statement.

2. Tankless Instantaneous Water Heater

The S500e ditches the warm-water reservoir tank that mid-range bidets rely on entirely. Instead, it heats water on-demand — in real time. That means continuous warm water from the first second to the last. No temperature drop halfway through.

Water temperature is adjustable across five levels — up to 104°F. And because the system only heats water when you actually need it, it’s more energy-efficient than tank-based models sitting idle and burning power all day.

3. Five-Mode Spray System with Dual-Action Wand

The wand offers five cleansing modes. Rear. Rear Soft. Front. Wide Front. Each one with adjustable pressure across five levels.

On top of that — oscillating and pulsating functions give you a level of personalization most bidet seats simply don’t offer. Oscillating moves the nozzle back and forth for broader coverage. Pulsating delivers a rhythmic, massage-like pulse. For a product this technically packed — the controls remain surprisingly intuitive through the wireless remote.

4. Heated Seat with Wireless Touch Remote

The seat maintains adjustable warmth between 82°F and 97°F. On winter mornings, that’s less of a feature and more of a necessity. The illuminated touchpad remote stores two user memory settings — so every person in the household can have their preferences saved and ready at the press of one button. It docks neatly on the wall when not in use. And thanks to radio-frequency sensing, it doesn’t need a direct line-of-sight to work. Point it wherever you like.

5. Slim Contemporary Design

The S500e’s lid sits flush with the toilet bowl. That gives it a seamlessly integrated look that most standard bidet seats — with their bulky back-end tanks — simply cannot match. Most bidet seats look like an afterthought bolted onto your toilet. This one looks like it was always supposed to be there.

At approximately 4 inches tall at the rear, it’s among the slimmest profiles in its class — a detail that matters more than people expect once they see it in person.

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My TOTO S500e Testing Experience — What I Actually Found (Review)

1. The First Use is Genuinely Disorienting (In the Best Way)

I’ll be honest.

The first time the PREMIST fired off before I even sat down, I thought something had gone wrong.

It hadn’t.

That quiet little mist is the S500e quietly preparing for you. And once you understand that, it starts to feel less like a toilet accessory — and more like something that actually has better bathroom manners than most humans I know.

The cleaning experience is where this seat earns its price tag.

The dual-action spray — with its oscillating movement — covers more area than a fixed-point nozzle. The warmth of the water stays consistent throughout. That’s something tank-based bidets simply can’t promise.

I ran extended testing sessions — bear with me — specifically to see if the tankless heater ever dropped temperature.

It didn’t. Not once.

That might sound like a boring technical detail. Until you’ve used a budget bidet that goes cold after 30 seconds — and suddenly you’re reconsidering all your life choices.

The five pressure levels give you a range from “gentle morning greeting” to “I mean business.”

Both the oscillating and pulsating functions add a surprising degree of personalization. After adjusting the settings a few times, the two-user memory function becomes genuinely useful — each person in the household can store their preferred configuration and pull it up without fiddling through menus.

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2. EWATER+ in Practice: Does It Actually Keep Things Cleaner?

Yes. Measurably.

After regular use, the bowl noticeably accumulated less residue between cleanings — compared to a standard toilet in the same bathroom.

Is this due entirely to PREMIST preventing adhesion? Or EWATER+ doing its sanitizing thing? Probably both working together.

What I can say is that the wand — the one component on any bidet seat that makes people uncomfortable to think about — genuinely self-sanitizes before and after every use. Without any intervention from you.

For anyone with an immune-compromised family member, an elderly parent, or just a strong preference for not thinking about cross-contamination — this feature alone justifies serious consideration.

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3. Accessibility: A Legitimate Life-Changer for the Right User

One of the most striking patterns across real-world user experiences is how transformative this seat is for people with limited mobility.

Post-surgical recovery. Conditions that make independent toileting difficult. These are real use cases — and the S500e handles them seriously.

A disabled user’s caregiver replaced an S300e after nine years of near-daily use.

They described the S500e as “a life-saver.”

A urologist reportedly recommended this specific model for patients dealing with urinary tract infections.

These aren’t edge cases.

The S500e’s hands-free, fully automated hygiene experience has a real, practical impact on independence and dignity for people who need it most.

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4. The Heated Seat: Quietly Underrated

On cold mornings, the heated seat shifts from a luxury feature to something you start quietly depending on.

The warmth is adjustable and gentle. Not hot in a way that’s startling — but present in a way you notice its absence the moment you use a regular toilet somewhere else.

After switching to the S500e, returning to a standard cold seat anywhere else feels borderline offensive.

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5. Design and Fit: Mostly Excellent, One Note

The slim profile looks genuinely premium.

It sits flush with the bowl in a way that makes your toilet look like it cost three times more than it did. The contemporary lid design is clean and minimal. The overall footprint is more restrained than most bidet seats in this price range.

One practical note worth flagging: because the back of the seat is raised slightly more than a standard lid, some users find themselves sitting a touch further forward than usual. It’s a minor adjustment — but worth knowing going in.

The wireless remote is responsive and logically laid out. The touchpad buttons are well-spaced. The radio-frequency connection means you don’t have to aim it directly at the seat.

The two-user memory function is genuinely handy.

But the remote isn’t backlit. For a seat this expensive, that’s a peculiar omission. Using it in a dark bathroom means either turning on the light or pressing buttons by feel. It works fine with some practice — but it’s the kind of detail that makes you wonder who approved the final spec sheet.

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6. Installation: Easy, With One Known Wrinkle

The main unit installs cleanly.

Most users complete it in under an hour — no professional help needed. TOTO provides a solid instructional video that covers the basics well.

The one consistent area of friction is the T-adapter water connection.

A number of buyers found minor leaks at the junction where the T-adapter meets the toilet’s fill tube. This happens primarily because plastic-to-metal fittings don’t always seal perfectly with the stock washers.

The fix is simple: pick up a cone-shaped rubber grommet at any hardware store before you start. Issue resolved.

Alternatively, replacing the toilet’s fill valve with a Fluidmaster PRO45B — a brass-shanked model at around $15 — makes the whole connection significantly more reliable.

Neither fix is complicated. It’s just the kind of prep tip that saves you a second trip to the hardware store.

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7. The S500e Has an Extra Energy-Saver Mode 

Both offer energy-saver modes, but the S500e Eco mode is slightly different.  

The main energy-zapping components of a bidet are the heated seat and water heater. Since the two bidets share the same water heater (the most efficient kind), that leaves the heated seat to consider.

Both the S300e and S500e come with these Eco modes: 

• Timer Energy Saver. This mode turns off the heated seat during a specified time. It’s for those who want to save energy during a preset length of time—maybe during work hours or when you’re away from home traveling, etc.  
• Auto Energy Saver. The bidet detects and memorizes time periods of infrequent use and automatically lowers the toilet seat temperature during these periods. 

The S500e has a third Eco mode called the Auto Energy Saver + mode that turns off the seat during periods of infrequent bidet use, instead of just turning the seat tempt down. It also has a fourth mode that combines the above Eco modes for max savings. 

The S300e has third mode that combines the two modes above (standard Auto Energy Saver and Timer Energy Saver) for increased energy savings. 

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All Versions of the S300e Lack Auto Flush Compatibility 

The other main difference between the two is that the S500 series bidets (S500e and S550e) are available with auto flush capability.  

Basically, if you have a certain type of toilet, you can sync it up with the wireless control to be able to flush the toilet remotely. 

I’m not really sure this matters that much. The auto-flush feature is only available with certain TOTO toilets: 

• The Aimes, NEXUS, Legato, and Aquia IV Dual Flush WASHLET+ one-piece toilets. 
• The Nexus, Aquia IV Dual Flush, and Connelly two-piece toilets. 

Most reading this article won’t need to consider this extra “perk”.

People purchase TOTO bidets for use on all sorts of toilets from other manufacturers, so most won’t be able to use this feature. 

Plus, those that have TOTO toilets may have different models than the ones just listed–TOTO toilets that are not Auto Flush capable.

Finally, auto-flush toilets flush automatically (as the name implies), when the user gets up, so I’m not sure why you’d need a remote control for manual flushing.  

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Features Both Bidets Are Lacking 

So, the S300e and S500e are pretty much the same, just as the S350e and S550e are basically the same. Which is why I recommend the S550e if it’s around the same price (it usually is).

With the S300e and S500e, there’s no night light to illuminate the bowl and no auto-open/close seats and lids, two features offered by their more sophisticated successors.  

They do light up the toilet bowl for certain functions, but there is no continuous night light feature with either. 

With the S350e and S550e, you can open and close the bidet seat and lid using the wireless remote. Instead, the S300e and S500e come a slow-close seat and lid.  

With a slight-nudge, the slow-close seat and lid take it from there, softly closing on their own. This helps save wear and tear in the long term. 

Still, having auto-open/close seats and lids would be nice.

Quick note: if you check the product page and spec sheet for the S500e, you won’t find a soft-close seat/lid advertised, but it does come with this feature.  

TOTO S500e vs S300e: Comparing Features and Specs 

So, there’s not a huge difference between the two bidets in terms of the features offered. But they do differ in certain specs. 

Water Temperature 

Both the S300e and S500e: 

• Come with a tankless water heater for instant and endless warm water. 
• Allow you to choose between “Off” and settings that range from 86° F to the highest of 104° F. 

Water Pressure 

The S300e:  

• Adjustable pressure allowing you to choose between 5 settings. 
• Decent water pressure with an output of 0.07 to 0.11 gal (or 0.27 – 0.43 L) per minute. 
• There’s no “strong” or “turbo” mode, but the bidet isn’t known for complaints of low pressure. 

The S500e: 

• Adjustable pressure w/5 settings.  
• Good water pressure with an output of 0.08 to 0.11 gal (or 0.32 – 0.43 L) per minute. 
• While, there’s no strong turbo mode, some have noted extra-strong pressure with this model and the S550e. I’d imagine the same is true for the S300e. 

Comfort and Convenience 

The S300e and S500e both come with: 

• A warm air dryer with five variable temperature settings. 
• An illuminated wireless handheld remote with easy-to-read controls and magnetic wall-mounted cradle. 
• User presets, allowing two regular bidet users to save their preferences for things like water pressure, temperature, and wand position. 
• Continuous contour for plenty of sitting room upfront. 
• Built-in air deodorizing system. 
• Heated seat with adjustable temperature. You can choose between “OFF” and settings that range from 82 – 97 °F. 

The S500e only: 

• If you see “AT” in the SKU, then the bidet will be compatible with Auto Flush toilets. 
• The two compatible versions include the SW3044AT40 (Classic) and SW3046AT40 (Contemporary). 

Seat and Lid 

The S300e and S500e both come with: 

• Quick-release docking station for easy bidet removal and cleaning.  
• Soft-Close seat and lid to save wear and tear. 

Spray Capability 

The S300e and S500e both come with: 

• A single spray wand with multiple spray holes for posterior and front feminine hygiene. The wands are adjustable to 5 positions for max accuracy. 
• The wand is made of high-quality plastic, not stainless steel. 
• Multiple spray settings: Rear (regular), Rear Soft, Front (regular) and Front Wide.  
• There is no Turbo or “strong” spray mode, though the water pressure is decent. 
• The Rear Soft mode is for soothing irritated skin and for those who prefer a softer spray. It’s similar to the Sitz Bath mode you’ll see on other bidets. 
• The Wide Front spray pattern covers a wider area.  
• Both come with an oscillating spray function. When activated, the oscillating mode causes the wand to move back and forth for a more thorough wash and greater coverage.  
• Massage/pulse spray setting provides a massage-like effect by rotating hard and soft water pressure.  

Safety and Sanitation 

The S300e and S500e both come with: 

• Automatic self-sanitizing nozzle(s). Like with most luxury bidets, the wands on the S300e and S500e self-rinse before and after each use and allow for on-demand self-rinsing via the wireless remote. 
• The wands can be extended for periodic manual cleaning. 
• In addition to self-cleaning, the wands self-sanitize by rinsing with EWATER+, which is water that contains electrolytes that form sodium hypochlorite. NaOCl is a natural antimicrobial substance and helps prevent waste (read: poop) from sticking to the wands by creating a slippery surface. 
• Both the S300e and S500e spritz the toilet bowl with EWATER+ using PREMIST technology. PREMIST creates a slippery surface keeping waste from sticking to the inside of the toilet bowl.  
• And, unlike the TOTO K300 which only pre-mists the bowl, the 300 and 500 series bidets go a step further by spraying the bowl after each use.  
• Finally, both bidets have a safety sensor which, when activated, prevents the bidet from being operated when the toilet isn’t unoccupied. This prevents unwanted surprises in case someone accidentally hits one of the controls. This feature is especially useful for kids and senior adults.

Recommended Reading:

• Best Bidets for Elongated Toilets
• TOTO C5: Every Feature Tested Practically
• TOTO K300: Every Feature Tested Practically

Top 3 Bidets with the Strongest Water Pressure: Insights from Industry Standards

TOTO Washlet S300e vs S500e: The Bottom Line 

So, there you have it. 

The S300e and S500e are essentially the same, with the S500e slightly edging out the S300e in one or two areas. The main difference is that the S500e offers an extra version with a more contemporary look. If you can do with the Classic look, then go with the cheaper of the two. 

The two bidets tend to be found for the same price and prices can fluctuate. Hence, you should go with whichever happens to be cheaper at the time of purchase.  

The only exception is if you really like the look of the contemporary S500e enogh to warrant any added cost. Again, prices fluctuate and the contemporary S500e may not cost any extra. 

As mentioned above, if the S550e is around the same price when you’re doing your research—which it often is at various retailers — I’d recommend getting that one since it does have a few extra features. 

The S550e has an auto open/close seat/lid and a bowl night light, etc. Plus, like the S500e, it’s also available in Contemporary and with AutoFlush compatibility.

That’s it for now. Thanks for reading.