The TOTO WASHLET KS6 is an online-exclusive bidet seat that packs TOTO’s most advanced hygiene technology into a slim, refined package — and it’s positioned as the direct successor to the K300.
In this review, you’ll get a complete breakdown of its features, performance, and whether it’s genuinely worth the investment for your bathroom.
| Specification | Detail |
|---|---|
| Image |  |
| Model Number | SW3946#01 |
| Dimensions (L x W x H) | 25-5/16″ x 15-1/4″ x 11-13/16″ |
| Water Heating | Instantaneous (tankless) — unlimited warm water |
| Wash Modes | Rear, Soft Rear, Front, Oscillating, Pulsating (5 settings) |
| Hygiene Tech | EWATER+ (auto wand clean), PREMIST, CLEAN RESIN |
| Controls | Wireless illuminated remote (handheld or wall-mountable), 4 user presets |
| Heated Seat | Yes — 5 temperature levels |
| Warm Air Dryer | Yes — 3 temperature settings |
| Night Light | Yes — auto-sensing LED bowl light |
| User Presets | 4 individual user memory profiles |
| Colors Available | Cotton White only |
| Toilet Compatibility | Elongated only (no French curve) |
| Warranty | 1-year limited |
| Buy Now |  |
| ✅ Pros | ❌ Cons |
|---|---|
| Unlimited warm water from the very first second | Elongated toilets only — no round version available |
| EWATER+ auto-cleans the wand before and after every single use | Cotton White only — no color options for warmer-toned bathrooms |
| PREMIST pre-wets the bowl, dramatically reducing waste adhesion | Dryer has only 3 temperature levels (vs. 5 on some competitors) |
| CLEAN RESIN surfaces resist grime and bacterial buildup passively | Online-exclusive — no showroom availability to see it in person |
| 4 individual user presets — ideal for multi-person households | No auto-open/close lid (reserved for the S7A) |
| Slim 5.5″ rear profile — sleeker than older tank-style seats | Requires a GFCI outlet within 3 feet of the toilet |
| Auto-sensing LED night light guides you without waking the room | 1-year limited warranty is standard but shorter than Brondell’s 3-year |
Check its current price on Amazon
Is the TOTO WASHLET KS6 Worth It?
Yes — emphatically so, if you own an elongated toilet and want the most hygiene-complete bidet seat TOTO offers at this price point.
The KS6 is the direct replacement for the K300, and it takes everything that made that seat popular and upgrades it across the board: auto EWATER+ wand cleaning (not just on-demand), CLEAN RESIN surfaces, a night light, four user presets instead of two, and an adjustable spray position.
If you’ve been browsing our bidet toilet seat comparison chart trying to figure out where the KS6 lands in the lineup, the short answer is this: it sits confidently between the S5 and the S7 in terms of feature density, but at a price that often undercuts the S5 — making it one of the best-value premium seats TOTO has ever released.
It won’t suit everyone — if you have a round toilet, need round/biscuit color options, or want auto-flush compatibility, you’ll need to look elsewhere. But for the right buyer, this seat delivers a genuinely spa-like experience that’s hard to beat at this price.
Design and Build Quality
The KS6 cuts a low, confident profile on your toilet — its 5.5″ rear height is about 19% slimmer than older tank-style seats, and the seamless seat design eliminates the visible gap between the seat and the body that made older WASHLETs look clunky.
The overall form is traditional rather than contemporary — TOTO describes the KS6 as a classic curved lid design, in contrast to the more modern telescoping lid on the S5. If you prefer a seat that blends quietly into your bathroom without drawing attention, the KS6’s understated aesthetic is genuinely appealing.
Build quality is exactly what you’d expect from TOTO — solid, precise, and built to last. The SoftClose lid closes with a whisper-quiet motion that instantly signals quality the moment you touch it. The mounting bracket uses a quick-release docking system, so removal for cleaning or reinstallation takes seconds.
One thing to be aware of before buying: the KS6 requires at least 2 inches of flat space between the toilet tank and the seat mounting holes, and it won’t fit toilets with a “French curve” tank design. Measure before you order — our guide to the best bidets for existing toilets covers exactly what measurements to take.
Cleaning Performance
This is where the KS6 genuinely shines, and what separates it from seats in a similar price range.
TOTO’s three-layer hygiene system works together in a way no single technology could match on its own. Before you even sit down, PREMIST sprays the inside of the bowl with a fine mist of water — this dramatically reduces how much waste sticks to the porcelain surface, which means you spend less time scrubbing the bowl between flushes.
Once you’re done, EWATER+ automatically cleans the wand inside and out with electrolyzed water — both before and after every use, and between each spray setting selection. This is a meaningful upgrade over the K300’s on-demand EWATER+, which required you to trigger the cleaning cycle manually. On the KS6, hygiene happens automatically, every single time.
CLEAN RESIN coats the wand and seat surfaces with an antimicrobial layer that passively resists grime and bacterial buildup between cleaning sessions. If you’ve ever looked at an older bidet nozzle and wondered how clean it really is, CLEAN RESIN addresses exactly that concern without any effort from you.
The spray itself delivers five wash modes — rear, soft rear, front, oscillating, and pulsating — with five pressure levels and an adjustable spray position, which lets you dial in the exact angle that works best for you. That last feature was notably absent on the K300 and adds real comfort for users who’ve felt other seats hit at an imprecise angle.
For more detail on how self-cleaning nozzle systems compare across brands, our guide to the best heated bidet toilet seats covers the major options side by side.
Comfort Features
Day-to-day comfort on the KS6 is genuinely excellent. The heated seat offers five temperature levels, so whether it’s the middle of winter or a humid summer night, you can find a setting that feels right.
Warm water is instantaneous — there’s no tank that runs cold after 30 or 60 seconds, and no warm-up wait when you first sit down. This is the single most impactful comfort feature on any premium bidet seat, and the KS6 delivers it flawlessly.
The warm air dryer runs at three temperature settings and does a thorough job of drying without taking forever — a common complaint with lower-quality dryers. The automatic deodorizer neutralizes odors in real time rather than masking them, which makes the bathroom noticeably fresher for everyone who uses it.
The auto-sensing LED night light is a small touch that genuinely improves nightly bathroom visits. It illuminates the bowl automatically when you enter the bathroom in the dark, eliminating the “cold seat in complete darkness” experience that makes middle-of-the-night trips uncomfortable. If you’ve been considering a bidet for seniors in your household, this feature alone is worth calling out — it meaningfully improves safety at night.
Controls and Installation
The KS6 ships with an illuminated wireless remote that can be held in hand or slotted into a wall-mount dock. Four individual user presets mean every person in your household can save their preferred water temperature, pressure, spray position, and seat warmth — and recall it instantly with a single button.
The remote is intuitive enough that most users are comfortable with it within the first few uses. The buttons are logically grouped and clearly labeled, and the backlighting makes them easy to read in any lighting condition.
Installation is a straightforward DIY job — no plumber required. You’ll need a Phillips-head screwdriver and about 45 minutes. The KS6 connects to your existing toilet’s water supply line via a T-connector and plugs into a standard 120V GFCI outlet. TOTO includes all hardware in the box.
The one non-negotiable: a GFCI outlet within 3 feet of the toilet. If yours isn’t, factor in the cost of having an electrician install one before budgeting for the seat. If you’re new to bidet installation, our existing toilet bidet guide walks through the full process step by step.
Who Is the TOTO WASHLET KS6 Best For?
The KS6 is an ideal pick for buyers who want TOTO’s best mid-premium hygiene technology in an online-only package that often prices more competitively than the S5.
It’s particularly well suited for multi-person households — four user presets is a real differentiator from most seats in this price class, which typically offer only two. If you’re a family of three or four where everyone has different wash preferences, the KS6 handles that without anyone needing to readjust settings every time.
It’s also a strong choice for buyers upgrading from the K300, the A100, or any older tank-heater seat. The jump in hygiene technology is substantial — auto EWATER+, PREMIST, and CLEAN RESIN together create a noticeably cleaner bathroom with far less manual effort.
If you’re comparing it against other premium seats, take a look at our Brondell Swash 1400 vs TOTO Washlet S5 comparison — many of the same considerations apply when weighing the KS6 against the Swash. And if you want to see where the KS6 fits within TOTO’s full lineup, our TOTO C5 vs S7 breakdown provides helpful context on the brand’s tiered feature structure.
If you have a round toilet or need Colonial White, the KS6 simply won’t work for your bathroom — check our comparison chart for round-compatible alternatives. And if you want auto-open/close lid functionality, step up to the S7A. But for the vast majority of buyers with a standard elongated bowl, the KS6 delivers everything you actually need at a price that makes it one of the most compelling seats in TOTO’s current range.
FAQ
Is the TOTO WASHLET KS6 a replacement for the K300?
Yes. The KS6 is TOTO’s designated successor to the K300, which is being phased out. The KS6 upgrades the K300 in several meaningful ways: EWATER+ now runs automatically before and after every use (not just on-demand), the spray position is adjustable, there are four user presets instead of two, a night light is included, and CLEAN RESIN adds passive antimicrobial protection to the wand and seat. The core technology — instantaneous water heating, PREMIST, wireless remote — carries over from the K300 to the KS6.
Does the TOTO WASHLET KS6 fit round toilets?
No. The KS6 (SW3946) is designed exclusively for elongated toilet bowls. If your toilet is round, this seat won’t fit correctly. Before purchasing any bidet seat, measure the distance from the front of the bowl to the mounting holes — elongated toilets typically measure around 18.5 inches, while round bowls measure around 16.5 inches. Our guide on bidets for existing toilets explains how to measure your bowl correctly.
What is the difference between the TOTO WASHLET KS6 and S5?
Both seats deliver instantaneous warm water, EWATER+ wand cleaning, PREMIST, four user presets, a night light, heated seat, dryer, and deodorizer. The main differences are aesthetic and logistical. The S5 has a modern telescoping lid and is available in multiple colors (Cotton White, Sedona Beige) and both elongated and round shapes. The KS6 has a classic curved lid, is Cotton White and elongated only, and is an online exclusive. Performance-wise, they’re nearly identical — the KS6 adds CLEAN RESIN, which the S5 lacks. Many buyers find the KS6 slightly better priced online, making it an excellent value when the aesthetic difference doesn’t matter.
How does the TOTO WASHLET KS6 compare to the S7?
The S7 is TOTO’s premium tier below the auto-open S7A. Compared to the KS6, the S7 adds EWATER+ coverage for both the wand and the toilet bowl (the KS6 covers the wand only), a contemporary flush lid design, auto-flush kit compatibility, and a wider front cleaning setting for enhanced feminine wash. The S7 also sits slightly lower on the bowl at 4.1″ rear height vs. the KS6’s 5.5″. If bowl EWATER+ and a more modern aesthetic matter to you, the S7 is worth the premium. If you’re happy with wand-only EWATER+ and want to save money without sacrificing comfort, the KS6 is the smarter buy. See our full S7 comparison guide for a deeper breakdown.
Conclusion
The TOTO WASHLET KS6 is a genuinely outstanding bidet seat for anyone with a standard elongated toilet who wants TOTO’s best hygiene technology at a price that makes sense.
The combination of instantaneous warm water, automatic EWATER+ wand cleaning, PREMIST bowl misting, CLEAN RESIN passive protection, four user presets, and an auto-sensing night light is a feature set that rivals or beats most seats costing significantly more.
The trade-offs are real but narrow: elongated only, Cotton White only, no auto-flush, and a 1-year warranty. If those limitations don’t apply to your situation, you’re looking at one of the best bidet seats in the mid-premium category right now.
Before you buy, also take a look at our bidet toilet seat comparison chart to see how the KS6 stacks up against the full field — and our guide to the best bidets for existing toilets if you want to make sure your bowl is compatible before ordering.
