Both the TOTO Washlet KS6 and S7 sit at the premium end of the WASHLET lineup — but they’re built for very different buyers, and choosing the wrong one could leave you overspending or under-equipped.
In this breakdown, you’ll get a clear, honest look at how these two seats compare so you can make the right call for your bathroom and budget.
| Feature | TOTO Washlet KS6 (SW3946) | TOTO Washlet S7 (SW4726AT40) |
|---|---|---|
| Image |  |
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| Dimensions (L x W x H) | 25 5/16″ x 15 1/4″ x 11 13/16″ | 20 7/8″ x 15 1/16″ x 4 1/16″ |
| Water Heating | Instantaneous (unlimited) | Instantaneous (unlimited) |
| EWATER+ Coverage | Wand only | Wand + toilet bowl |
| PREMIST | Yes | Yes |
| Spray Settings | 5 (incl. oscillating + pulsating) | 5 + wide-front wash |
| User Memory Presets | 4 | 4 |
| Auto-Flush Compatible | No | Yes (kit sold separately) |
| Warranty | 1 Year Limited | 2 Year Limited |
| Buy Now |  |
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1. TOTO Washlet KS6 (SW3946#01)
The TOTO Washlet KS6 is TOTO’s newest online-exclusive premium seat, arriving as the direct successor to the beloved K300 and stepping the formula up considerably.
Where the K300 had solid core features, the KS6 adds both PREMIST bowl misting and EWATER+ wand cleaning — two of TOTO’s signature hygiene technologies — all wrapped in a sculpted, minimalist silhouette designed for buyers who want quiet sophistication without paying flagship prices.
Features
- Instantaneous tankless water heating for unlimited warm water on demand
- EWATER+ automatically cleans the wand with electrolyzed water before and after every use
- PREMIST coats the toilet bowl before each use to prevent waste from adhering
- CLEAN RESIN wand and seat surface that actively repels buildup
- 5 spray settings including oscillating and pulsating modes, front and rear wash
- 4 user memory presets via illuminated wireless remote (wall-mountable)
- Heated seat with 5 temperature settings, warm air dryer, air deodorizer, and soft nightlight
- WASHLET+ compatible for concealed cord and hose installation
Pros
- Full TOTO hygiene suite (PREMIST + EWATER+) at a lower price point than the S7
- Instantaneous water heating — never runs cold, no matter how long the wash
- Beautifully sculpted design with a clean, seamless aesthetic
- 4-user preset remote makes it genuinely practical for multi-person households
- Great value entry point into TOTO’s premium tier
Cons
- EWATER+ covers the wand only — not the toilet bowl like the S7
- No auto-flush compatibility
- Only 1-year warranty compared to the S7’s 2 years
- No wide-front wash setting for enhanced feminine cleanse
Check its current price on Amazon
2. TOTO Washlet S7 (SW4726AT40#01)
The TOTO Washlet S7 is TOTO’s current flagship bidet seat — the most feature-complete seat in the lineup short of the auto-open S7A.
It replaced the S500e with a radically slimmer profile at just 4.1″ at the rear, a contemporary lid that sits flush with the toilet bowl, and a critical hygiene upgrade: EWATER+ now cleans not just the wand, but the toilet bowl itself after every flush.
Features
- Instantaneous tankless water heating for unlimited warm water
- EWATER+ cleans both the wand AND the toilet bowl after every use
- PREMIST wets the bowl before each use, reducing waste adhesion dramatically
- 5 spray settings + dedicated wide-front wash for enhanced feminine hygiene
- 4 user memory presets, illuminated touch-button horizontal remote
- Heated seat, warm air dryer, power deodorizer, and a brighter nightlight
- Auto-flush compatible (kit sold separately) on TOTO T40 WASHLET+ toilets
- Ultra-slim 4.1″ rear height — among the slimmest seats available anywhere
- WASHLET+ compatible for fully concealed power cord and water supply line
Pros
- Full bowl EWATER+ hygiene — the toilet bowl actively cleans itself between uses
- Dramatically slim profile creates a near-integrated look on any elongated toilet
- Wide-front wash provides a more thorough feminine cleanse
- Auto-flush capability for a fully hands-free bathroom experience
- 2-year warranty — double the KS6’s coverage
- Power deodorizer mode for stronger odor elimination when needed
Cons
- Significantly higher price point than the KS6
- No automatic lid open/close (that’s the S7A)
- Remote removed the LCD screen, making some advanced setting adjustments less intuitive
Check its current price on Amazon
Hygiene Technology: EWATER+ Depth Is the Biggest Divide
Both seats use TOTO’s EWATER+ and PREMIST systems — but there’s a meaningful gap in how far that hygiene coverage extends.
On the KS6, EWATER+ cleans the wand before and after every use.
That’s excellent wand hygiene, and it’s one of the key reasons the KS6 sits above mid-range bidet seats in the market.
The S7 takes it further by also misting the toilet bowl with EWATER+ electrolyzed water after every flush — meaning your bowl is being actively sanitized between every use without any effort on your part.
For hygiene-focused buyers, this is the single most important distinction between these two seats.
Both include PREMIST, which pre-wets the bowl before you sit so waste is far less likely to stick in the first place.
You can dig deeper into how these technologies compare across TOTO’s full lineup in our bidet toilet seat comparison chart.
Winner: TOTO Washlet S7 — bowl EWATER+ is a genuinely superior hygiene system.
Design and Profile: The S7 Is Dramatically Slimmer
The KS6 has a sculpted, refined look that sits well on most elongated toilets without looking bulky.
But the S7’s rear height of just 4.1″ is in a different category entirely.
Its contemporary lid is engineered to sit flush with the toilet bowl, creating the visual impression of an integrated bidet toilet rather than a seat bolted onto a regular one.
When paired with a TOTO WASHLET+ toilet that conceals the power cord and water line inside the unit, the S7 is nearly indistinguishable from a full smart toilet combo.
If your bathroom is a design priority, the S7 wins this category decisively.
Our TOTO C5 vs S7 comparison has more detail on how the S7’s silhouette compares to other seats in TOTO’s lineup.
Winner: TOTO Washlet S7 — the slimmest, most integrated-looking seat TOTO makes short of the S7A.
Wash Performance and Comfort: A Very Close Match
Both seats use TOTO’s AIR-IN WONDER WAVE technology, which infuses air into each water droplet to create a softer, wider spray that cleans effectively without being harsh.
Both offer 5 spray settings, oscillating and pulsating modes, unlimited warm water, an adjustable heated seat, a warm air dryer, and a deodorizer.
The S7 adds a wide-front wash setting — a broader feminine wash mode that provides more coverage than the standard front wash on the KS6.
The S7’s nightlight is also notably brighter, which makes a real difference during nighttime bathroom visits.
For most users, daily comfort on both seats is going to feel exceptional and roughly equivalent.
The S7 earns a narrow edge for female users and light-sensitive nighttime users.
If you’re comparing TOTO’s spray against other top brands at this price tier, our best heated bidet toilet seats guide covers the full competitive landscape.
Winner: TOTO Washlet S7 — slightly ahead on wide-front wash and nightlight brightness.
Value, Warranty, and Smart Features
The KS6 costs substantially less than the S7, and that price difference is real money.
For that lower price, you still get PREMIST, EWATER+ wand cleaning, instantaneous heating, 4-user remote, and WASHLET+ compatibility — a very strong package.
The S7’s 2-year warranty versus the KS6’s 1 year is a meaningful difference at premium price points.
The S7 also adds auto-flush capability when paired with a TOTO T40 toilet and a separately purchased kit — a feature the KS6 simply cannot replicate.
For buyers building a full TOTO WASHLET+ bathroom setup, that auto-flush integration could be the deciding factor entirely.
For context on how these seats fit into the broader TOTO ecosystem, see our TOTO AP vs EP wall-hung toilet comparison and our highest rated bidet toilet guide if you’re weighing an integrated smart toilet instead.
Winner: TOTO Washlet S7 — better warranty, auto-flush capability, and superior value across the full feature set.
Verdict — Which One Should You Buy?
Both seats are genuinely excellent, and either one represents a meaningful upgrade over virtually anything else in the bidet seat market.
But they’re built for different buyers.
Buy the TOTO Washlet KS6 if…
- You want TOTO’s full PREMIST + EWATER+ hygiene technology without paying flagship prices
- Budget is a real consideration and you’d rather save the price gap
- Bowl-level EWATER+ isn’t a priority — you’re comfortable cleaning the bowl on your own schedule
- You don’t need auto-flush or the ultra-slim profile
- You’re upgrading from the K300 and want a natural next step without jumping to the top tier
Buy the TOTO Washlet S7 if…
- You want TOTO’s absolute best bidet seat (short of the auto-lid S7A)
- Bowl hygiene automation is a priority — you want the toilet bowl cleaned after every use
- Aesthetics matter and you want the most integrated-looking seat possible
- You’re building a TOTO WASHLET+ bathroom and want auto-flush capability
- You want 2-year warranty coverage and the long-term peace of mind it brings
- The wide-front wash for enhanced feminine hygiene is important to you
If you’re still exploring options across the full bidet seat market, our best bidets for home use roundup and the bidet toilet seat comparison chart are excellent next reads.
FAQ
Is the TOTO Washlet KS6 a replacement for the K300?
Yes — the KS6 is the direct successor to the K300.
It keeps everything the K300 was known for (instantaneous heating, 4 user presets, illuminated wireless remote) and adds PREMIST bowl misting, which the K300 lacked entirely.
If you have a K300 and are looking to upgrade, the KS6 is the natural next step without going all the way to the S7.
What is the real difference between the KS6 and S7 EWATER+ systems?
Both seats clean the wand with EWATER+ electrolyzed water before and after every use.
The S7 goes further by also misting the toilet bowl itself with EWATER+ after every flush — actively sanitizing your bowl between every single use with no effort on your part.
The KS6’s EWATER+ covers only the wand, meaning you still need to clean the bowl manually on a regular basis.
For a full look at how these features compare across TOTO’s lineup, our bidet toilet seat comparison chart has a detailed breakdown.
Can the TOTO Washlet S7 be installed on any elongated toilet?
Yes — the S7 is compatible with most standard elongated toilets from any manufacturer.
It also works with TOTO’s T20/T40 WASHLET+ toilets, which conceal the power cord and water supply hose for a seamless, integrated look.
Toilets with a “French curve” design may not be compatible — always check your toilet’s measurements before ordering.
If you’re planning a full bathroom upgrade around a new toilet, check out our highest rated bidet toilet guide for integrated smart toilet alternatives worth considering.
Is the KS6 or S7 better for seniors or users with limited mobility?
Both seats are excellent for seniors — instantaneous warm water, adjustable heated seats, full remote-control operation, and soft nightlights cover all the key accessibility features.
The S7 adds the convenience of auto-flush compatibility (with a separately purchased kit), which is a meaningful independence upgrade for users who prefer a fully hands-free experience.
The KS6 delivers the same remote-control comfort at a more accessible price point.
For more on the features that matter most for older users, see our dedicated best bidets for seniors guide.
Conclusion
The TOTO Washlet KS6 and S7 are both outstanding seats, and either one will represent a genuine upgrade over virtually anything else in the bidet seat market.
The KS6 is the smarter buy for anyone who wants TOTO’s premium hygiene technology at a more manageable price without needing the full flagship experience.
The S7 is worth every extra dollar if you want total bathroom hygiene automation, the slimmest possible profile, a superior warranty, and auto-flush capability.
For most first-time buyers not building a full TOTO WASHLET+ ecosystem, the KS6 delivers remarkable value and should not be underestimated.
For buyers who want TOTO’s best and plan to keep it for years, the S7 is the definitive choice.
Still deciding or want to keep comparing? Browse our bidet comparisons archive or head to our best bidets for existing toilets guide for a broader look at what’s available right now.
