If you’re choosing between the TOTO Washlet S2 and the KS5, you’re weighing two strong contenders from the same trusted brand — each with a very different approach to hygiene and control.
This comparison breaks down every major difference so you can pick the one that fits your bathroom and your lifestyle best.
| Feature | TOTO Washlet S2 | TOTO Washlet KS5 |
|---|---|---|
| Image |  |
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| Dimensions (L x W x H) | 20.6″ x 15.2″ x 5.5″ | 20.6″ x 15.2″ x 6.3″ |
| Water Heating | Instantaneous (unlimited) | Instantaneous (unlimited) |
| Hygiene Tech | EWATER+ + PREMIST + CLEAN RESIN | CLEAN RESIN only |
| Controls | Side arm panel | Wireless illuminated remote |
| User Presets | None | 4 user memory presets |
| Spray Modes | Rear, Rear Soft, Front, Oscillating | Rear, Front, Oscillating, Pulsating |
| WASHLET+ Compatible | Yes | Yes |
| Buy Now |  |
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1. TOTO Washlet S2 (SW3346#01)
The TOTO Washlet S2 is the newest entry-level model in TOTO’s redesigned S series, replacing the discontinued C2 with a major upgrade: instantaneous water heating that delivers unlimited warm water from the very first second.
It packs TOTO’s most advanced hygiene trifecta — EWATER+, PREMIST, and CLEAN RESIN — into its most accessible price point, making it one of the most over-engineered entry seats on the market right now.
If you’ve been researching the best bidets for existing toilets and want TOTO’s signature sanitation technology without stretching your budget, the S2 delivers exactly that.
Features
- Instantaneous tankless water heating — unlimited warm water
- EWATER+ electrolyzed water cleans the wand inside and out before and after every use
- PREMIST automatically mists the bowl before each use, preventing waste from sticking
- CLEAN RESIN coating on the wand and seat repels bacteria and grime
- Side arm control panel with rear, rear soft, front, and oscillating spray modes
- Heated SoftClose seat with five temperature settings
- Warm air dryer, automatic deodorizer, and night light
- WASHLET+ compatible — conceals cords with compatible TOTO toilets
- 19% slimmer profile than previous C-series models
Pros
- EWATER+ and PREMIST together are the most advanced hygiene system at this price point
- Slim, modern profile fits a wide range of elongated toilets
- Unlimited warm water — no cold-water surprise mid-wash
- Auto energy-saver mode adjusts seat temperature when inactive
- Includes automatic deodorizer that many seats at this level skip
Cons
- No wireless remote — side arm panel only, which some users find less convenient
- No user memory presets — each user must manually adjust settings
- No pulsating spray mode (oscillating only)
- Available in elongated only (round option exists as SW3345)
For anyone prioritizing bowl and wand hygiene above everything else, the S2 is hard to match at its price point — it’s the seat that keeps itself, and your toilet bowl, cleaner with the least effort on your part.
Check its current price on Amazon
2. TOTO Washlet KS5 (SW3216#01)
The TOTO Washlet KS5 is a comfort-forward mid-range seat built around ease of use and multi-user flexibility.
Where the S2 focuses on hygiene automation, the KS5 doubles down on convenience — delivering an illuminated wireless remote, four programmable user memory presets, and a pulsating spray mode that the S2 doesn’t offer.
If you’re a household of two or more people who each want their own saved settings, the KS5’s four-preset remote makes it the more practical everyday choice, as explored further in our guide to the best heated bidet toilet seats.
Features
- Instantaneous tankless water heating — unlimited warm water
- Illuminated wireless remote control — can be mounted to the wall for easy access
- 4 user memory presets — each person in the house saves their own settings
- CLEAN RESIN self-cleaning wand — sanitizes inside and out before and after every use
- Rear, front, oscillating, and pulsating spray modes
- Heated SoftClose seat with adjustable temperature
- Warm air dryer with three temperature settings
- Night light and WASHLET+ compatibility
Pros
- Wireless remote is the more intuitive control experience for most users
- 4 user presets make it excellent for households with multiple people
- Pulsating spray adds a massage-like wash option the S2 doesn’t have
- Illuminated remote is especially practical in the dark
- WASHLET+ compatible — clean install when paired with compatible TOTO toilets
Cons
- No EWATER+ — wand is clean but doesn’t use electrolyzed sterilizing water
- No PREMIST — the bowl doesn’t get pre-wetted before each use
- Slightly higher profile than the slim S2
- Available in cotton white only
For a home with multiple users who want their own saved wash preferences and the comfort of a remote, the KS5 is the smarter fit — and its pulsating mode adds a layer of comfort that many users end up reaching for daily.
Check its current price on Amazon
Head-to-Head: Hygiene Technology
This is the single biggest differentiator between these two seats, and the S2 wins it decisively.
The S2 brings TOTO’s full hygiene trifecta: EWATER+ transforms tap water into a mild sterilizing agent that cleans the wand inside and out before and after every use; PREMIST coats the bowl with a thin film of water before you sit down, making waste far less likely to stick; and CLEAN RESIN repels bacteria and grime from both the wand and the seat surface.
The KS5 has only CLEAN RESIN — its wand self-cleans thoroughly, but without the electrolyzed water of EWATER+ and without PREMIST for the bowl.
If you’ve been looking at our bidet toilet seat comparison chart and bowl cleanliness is a priority, the S2 is the easy winner here — you’ll notice your toilet bowl stays noticeably cleaner between scrubbings.
Winner: TOTO Washlet S2
Head-to-Head: Controls and Daily Convenience
The KS5 takes this category without question.
The S2 relies on a side arm panel attached directly to the seat — functional, compact, and always within reach, but not the most intuitive experience if you prefer to adjust settings before sitting down or if you have limited mobility.
The KS5 comes with an illuminated wireless remote that can be handheld or mounted to the wall next to the toilet.
That wall-mount capability makes a real difference for accessibility — seniors, guests, or anyone who finds a side panel awkward will immediately appreciate the remote-first design.
For more on how controls affect the experience for older users specifically, our guide to the best bidets for seniors has a detailed breakdown of what to prioritize.
Winner: TOTO Washlet KS5
Head-to-Head: Multi-User Households
The KS5 wins this one by design.
With four programmable user memory presets, every person in your household can save their preferred water temperature, pressure, spray position, and seat warmth — and switch between profiles with a single button press on the remote.
The S2 has no memory presets at all.
That means every time a different person uses the S2, they need to manually re-adjust all settings from scratch.
For a single-person or couple household where preferences are similar, that’s no big deal — but in a home with three or four regular users, the KS5’s preset system saves a surprising amount of friction every single day.
It’s worth comparing both against the broader lineup in our best bidets for existing toilets roundup if you’re still deciding.
Winner: TOTO Washlet KS5
Head-to-Head: Spray Performance
Both seats deliver instantaneous warm water — no waiting, no cold shock at the start of a wash.
The S2 offers rear, rear soft, front, and oscillating spray modes — covering the full range of daily needs cleanly.
The KS5 adds a pulsating spray mode on top of oscillating, which creates a rhythmic, massage-style wash that many users find more comfortable for longer sessions or for users with sensitive skin.
Neither seat has a weak spray — both are well-engineered TOTO products — but the extra pulsating mode on the KS5 gives it a slight edge for comfort variety.
If spray performance is something you’re researching deeply, also take a look at how both seats compare to models like the Brondell Swash 1400 vs TOTO Washlet S5 comparison for a sense of what the wider market offers.
Winner: TOTO Washlet KS5 (by a narrow margin)
Head-to-Head: Value for Money
This comes down to what you value most.
The S2 gives you TOTO’s most sophisticated hygiene system at the lowest S-series price — EWATER+ and PREMIST genuinely reduce how often you need to scrub your toilet bowl, which is a real-world quality-of-life win.
The KS5 costs more but delivers a remote, four user presets, and the pulsating mode — features that many households will use every single day.
The S2 wins on sanitation engineering per dollar; the KS5 wins on comfort and convenience per dollar.
Neither is a bad deal — TOTO’s build quality and reliability make both seats worth the investment, as discussed further in our guide to the highest rated bidet toilets.
Winner: Tie — depends on your priorities
Verdict: Which One Should You Buy?
Buy the TOTO Washlet S2 if… you want TOTO’s best hygiene technology at the lowest price, you live alone or with one other person with similar preferences, you don’t mind adjusting settings manually, and you care deeply about keeping your toilet bowl and wand as sanitary as possible between cleanings. EWATER+ and PREMIST together genuinely reduce bowl grime — that matters in the long run.
Buy the TOTO Washlet KS5 if… you want a wireless remote-controlled seat, your household has two to four regular users who each want their own saved settings, you’d like the added comfort of a pulsating spray mode, and you prioritize ease of use and daily convenience over hygiene automation. The four-user preset system alone is worth the upgrade for most multi-person households.
Both seats are WASHLET+ compatible, both use instantaneous water heating, and both come with TOTO’s legendary build quality — you won’t regret either choice.
Still on the fence? The bidet toilet seat comparison chart at BideTalk gives you a broader side-by-side look at the full market, and the TOTO C5 vs S7 comparison covers the next tier up if you’re considering a bigger upgrade.
FAQ
Does the TOTO Washlet S2 have a wireless remote?
No — the S2 uses a side arm control panel attached directly to the seat. If a wireless remote is important to you, the KS5 is the model to choose, as it comes with an illuminated remote that can also be mounted to the wall.
What is PREMIST on the TOTO Washlet S2 and why does it matter?
PREMIST automatically sprays the inside of the toilet bowl with a fine mist of water before you sit down. This thin film of water prevents waste from adhering to the porcelain, which means your bowl stays cleaner between scrubbings and each flush is more effective. The KS5 does not include PREMIST.
Can both the S2 and KS5 fit my elongated toilet?
Both seats are designed for elongated toilets. They are compatible with most standard elongated bowls, though toilets with a “French curve” design where the tank meets the bowl on a slope may cause fit issues — always measure before ordering. You can find a detailed guide on toilet compatibility in our best bidets for existing toilets article.
Does the KS5 replace the C5?
No — the KS5 is a distinct model in TOTO’s lineup, not a direct C5 replacement. The C5 has been succeeded by the TOTO Washlet S5, which brings instantaneous water heating and other upgrades. The KS5 sits at a different position in the lineup with its emphasis on remote control and user presets rather than the advanced EWATER+/PREMIST hygiene stack.
Conclusion
The TOTO Washlet S2 and KS5 are genuinely great seats — they share TOTO’s build quality, instantaneous water heating, and WASHLET+ compatibility — but they serve different buyers.
The S2 is the hygiene-first choice: EWATER+, PREMIST, and CLEAN RESIN together create the cleanest wand and bowl experience at this price point, and the 19% slimmer profile is a nice bonus.
The KS5 is the comfort-and-convenience choice: a wireless illuminated remote, four user presets, and a pulsating spray mode make it the smarter pick for multi-person households and anyone who values an intuitive, remote-first experience.
If you’re still exploring your options, check out our full bidet toilet seat comparison chart and the Brondell CL1700 vs TOTO Washlet S2 comparison for two more great reads before you decide.
