If you’re choosing between the TOTO WASHLET KS6 and S5, you’re comparing two of the most capable mid-range bidet seats on the market right now.
Both share TOTO’s elite EWATER+ and PREMIST technology — but the differences in design, controls, and footprint could make one a much better fit for your bathroom than the other.
| Feature | TOTO WASHLET KS6 | TOTO WASHLET S5 |
|---|---|---|
| Image |  |
 |
| Model Number | SW3946#01 | SW3446#01 |
| Dimensions (L x W x H) | 25.3″ x 15.3″ x 11.8″ | ~21″ x 15″ x ~6″ |
| Water Heating | Instantaneous (unlimited warm water) | Instantaneous (unlimited warm water) |
| EWATER+ & PREMIST | Yes — wand cleaning | Yes — wand cleaning |
| Controls | Illuminated wall-mount remote | Slim wireless remote |
| User Presets | 4 | 4 |
| Colors Available | Cotton White only | Cotton White, Sedona Beige |
| Buy Now |  |
 |
1. TOTO WASHLET KS6 (SW3946#01)
The TOTO WASHLET KS6 is TOTO’s newest online-exclusive bidet seat, positioned as the upgraded successor to the highly popular K300.
It keeps everything buyers loved about the K300 — EWATER+, PREMIST, heated seat, warm air dryer — and adds a more refined sculpted silhouette with an illuminated remote that can be wall-mounted for the cleanest possible look next to your toilet.
The KS6 is built for buyers who want premium TOTO quality, a full-featured remote with a dedicated cradle, and the reassurance of EWATER+ wand cleaning at a price point well below the flagship S7.
Features
- Instantaneous tankless water heating — endless warm water on demand
- EWATER+ electrolyzed water wand self-cleaning before and after every use
- PREMIST bowl misting before each use to prevent waste adhesion
- 5 spray settings: rear, soft rear, front, oscillating, pulsating
- Heated SoftClose seat with 5 temperature settings
- Warm air dryer with adjustable temperature
- Automatic air deodorizer with carbon filter
- Built-in nightlight
- Illuminated remote with wall-mount cradle and 4 user memory presets
- CLEAN RESIN wand coating to repel bacteria and grime
- WASHLET+ compatible for concealed cord/hose installation
- Elongated fit, Cotton White (SW3946#01)
Pros
- Illuminated remote with wall-mount cradle looks and feels premium
- Sculpted low-profile silhouette that fits both classic and contemporary bathrooms
- Full EWATER+ and PREMIST system — the gold standard for TOTO hygiene
- Unlimited warm water with no tank to run out
- 4 user presets — great for multi-person households
- WASHLET+ compatible for a wire-free installation on supported toilets
Cons
- Available in Cotton White only — no Sedona Beige option
- Larger rear profile than the S5 — may look bulkier on some toilets
- Online exclusive — not available in physical showrooms
Check its current price on Amazon
2. TOTO WASHLET S5 (SW3446#01)
The TOTO WASHLET S5 is the direct successor to the beloved C5, and it’s a major step forward.
Where the C5 relied on a tank-style heater that ran cold after 30–60 seconds, the S5 delivers unlimited warm water instantly — a change that makes a noticeable difference in real-world use.
It’s 19% slimmer in profile than its predecessor, making it one of the sleekest seats in TOTO’s lineup, and it adds a nightlight and four user presets that the C5 never had.
Features
- Instantaneous tankless water heating — consistent warm water without a tank
- EWATER+ wand self-cleaning with electrolyzed water before and after use
- PREMIST bowl misting before each use
- 5 spray settings including oscillating and pulsating modes
- Heated SoftClose seat with 5 temperature settings
- Warm air dryer with 5 temperature settings
- Automatic air deodorizer
- Built-in nightlight
- Slim wireless remote with 4 user memory presets
- CLEAN RESIN wand coating
- WASHLET+ compatible
- Available elongated or round; Cotton White or Sedona Beige
- Named 2025 Wirecutter Top Pick
Pros
- Slimmer, more low-profile design — 19% thinner than the C5 it replaced
- Available in two colors: Cotton White and Sedona Beige
- Comes in both elongated and round bowl sizes
- Named a Wirecutter Top Pick — independently validated performance
- Same EWATER+ and PREMIST system as the KS6 at a comparable price point
- Slim wireless remote fits discreetly beside the toilet
Cons
- Remote is not illuminated — harder to read in low light than the KS6’s backlit remote
- No dedicated wall-mount cradle for the remote (mounts with adhesive strip instead)
- Slightly less sculpted aesthetic compared to the KS6’s contemporary silhouette
Check its current price on Amazon
Head-to-Head: KS6 vs S5
Hygiene Technology
Both seats use TOTO’s flagship hygiene stack: EWATER+ wand cleaning, PREMIST bowl misting, and CLEAN RESIN wand coating.
In practice, this means the wand is automatically cleaned with electrolyzed water before and after every single use, and the bowl is pre-wetted before you sit down so waste doesn’t stick.
You can read more about why these features matter in our bidet toilet seat comparison chart, which shows how TOTO’s hygiene system stacks up against every other major brand.
Neither seat edges ahead here — it’s a genuine tie.
Winner: Tie
Design and Profile
This is where the two seats diverge most visibly.
The KS6 has a sculpted, more architectural silhouette — it’s a heftier seat that commands attention on the toilet.
The S5 is 19% slimmer in profile and sits considerably lower on the bowl, giving it a cleaner, more modern look, especially when paired with a contemporary toilet.
If you want a seat that nearly disappears on the toilet, the S5 wins this category without question.
If you prefer a bold, sculpted seat that feels like a statement piece, the KS6 has the edge.
For buyers designing a complete bathroom upgrade, take a look at our TOTO AP vs EP wall-hung toilet comparison if you’re pairing either of these seats with a new toilet.
Winner: S5 (slimmer and more low-profile)
Controls and Usability
The KS6 ships with an illuminated remote that slots into a wall-mount cradle — a noticeably premium experience.
The backlit buttons are easy to read even in the dark, and the dedicated cradle keeps the remote in a fixed, tidy position beside the toilet.
The S5’s remote is slim and clean, but it is not illuminated and mounts via an adhesive strip rather than a dedicated cradle.
For buyers who use the bidet during nighttime bathroom trips — a common use case for heated bidet seats — the KS6’s illuminated remote is a real practical advantage.
Both remotes support 4 user memory presets, making them equally suited to multi-person households.
If remote usability and that wall-mounted cradle experience matter to you, the KS6 wins this category clearly.
Winner: KS6 (illuminated remote with dedicated wall-mount cradle)
Color and Compatibility Options
The S5 is available in both Cotton White and Sedona Beige, and it comes in both elongated and round bowl sizes.
The KS6 is currently offered in Cotton White only, for elongated bowls.
If your bathroom has warm-toned tiles or older fixtures and you need Sedona Beige to match, the S5 is your only option here.
For more guidance on TOTO’s color options, our TOTO Colonial White vs Cotton White guide explains the differences in detail.
If you have a round toilet, the S5 wins by default — the KS6 is elongated only.
Winner: S5 (two colors, two bowl sizes)
Value and Brand Positioning
Both seats sit in a similar price bracket, which makes this comparison unusually close.
The KS6 is an online-exclusive model — TOTO sells it through digital channels only, similar to how they positioned the K300.
The S5 is available more widely, including through TOTO’s authorized retailer network, and it’s earned a 2025 Wirecutter Top Pick designation — one of the most credible third-party endorsements a bidet seat can get.
For buyers who value independent validation and a seat with recognized credentials, the S5 has a small but meaningful edge.
That said, if you prefer the KS6’s illuminated remote and sculptural design, you’re not giving up anything significant in terms of features or TOTO build quality.
Our best bidets for home use guide is a great companion read if you’re still comparing across brands at this tier.
Winner: S5 (wider availability and Wirecutter recognition)
Verdict — Which One Should You Buy?
Both the KS6 and S5 deliver TOTO’s best-in-class hygiene technology, unlimited warm water, and four user presets — at a very similar price.
The decision comes down to two things: design preference and remote usability.
Buy the TOTO WASHLET KS6 if… you want an illuminated wall-mount remote that’s easy to use in the dark, you love the sculpted aesthetic, and Cotton White works for your bathroom.
Buy the TOTO WASHLET S5 if… you want the slimmest possible profile on your toilet, need Sedona Beige or a round bowl size, or want a seat that’s been independently named a Wirecutter Top Pick.
If you’re still exploring the broader TOTO lineup, the TOTO C5 vs S7 comparison covers how the mid-range tier stacks up against the flagship, and our TOTO C5 vs S5 guide explains what changed when the S series replaced the C series.
FAQ
Is there a TOTO WASHLET S6?
No — TOTO does not make a model called the S6.
The current S series lineup is S2, S5, S7, and S7A.
The KS6 (SW3946) is a separate model in TOTO’s online-exclusive KS series — it is not the same as an “S6,” and the two naming conventions come from different product families.
If you searched for “TOTO KS6 vs S6,” this comparison of the KS6 against the S5 is the most relevant matchup at that tier.
What did the TOTO WASHLET KS6 replace?
The KS6 (SW3946) is the successor to the TOTO WASHLET K300 (SW3036R), which has been discontinued.
The K300 was a popular online-exclusive model, and the KS6 carries forward all of its core features — EWATER+, PREMIST, instantaneous heating — in a refreshed silhouette with an improved illuminated remote.
Our TOTO S5 vs K300 comparison gives more context on how the two successor models from each line compare.
What did the TOTO WASHLET S5 replace?
The S5 (SW3446) replaced the discontinued TOTO WASHLET C5 (SW3084).
The S5 improves on the C5 in every meaningful way: it switches from a tank heater to a tankless instantaneous system, trims 19% from the profile, adds a nightlight, and upgrades from 2 user presets to 4.
See our full TOTO C5 vs S5 breakdown for a detailed look at what changed.
Do the KS6 and S5 both work with WASHLET+ toilets?
Yes, both seats are WASHLET+ compatible.
On a TOTO WASHLET+ ready toilet, the power cord and water supply hose route through the toilet body — completely out of sight — giving both seats the clean, wire-free look of an integrated smart toilet.
If you’re pairing either seat with a new toilet, our heated bidet toilet seats guide covers the top models that work well in a WASHLET+ setup.
Conclusion
The TOTO WASHLET KS6 and S5 are among the best mid-range bidet seats you can buy right now, and choosing between them is genuinely a matter of personal priorities rather than one being clearly better than the other.
The KS6 wins on remote experience and design character.
The S5 wins on slimness, color variety, bowl size flexibility, and independent acclaim.
Either way, you’re getting TOTO’s world-class EWATER+ and PREMIST hygiene system, unlimited warm water, and a seat built to last for years.
Still comparing your options across brands? Our bidet toilet seat comparison chart and best bidets for existing toilets guide are the perfect next reads.
