If you’re weighing the TOTO WASHLET S7A against the S550e, you need to know which seat truly delivers the better experience for your bathroom.
In this breakdown, you’ll get an honest, side-by-side look at both seats so you can make the right call — whether you’re upgrading from the S550e or deciding whether remaining stock is still worth buying.
| Feature | TOTO WASHLET S7A | TOTO WASHLET S550e |
|---|---|---|
| Image |  |
 |
| Dimensions (L x W x H) | 21.6″ x 15.3″ x 4.06″ | 21.6″ x 15.4″ x 4.81″ |
| Water Heating | Instantaneous (unlimited) | Instantaneous (unlimited) |
| EWATER+ Coverage | Wand, bowl & under-seat | Wand & bowl |
| User Presets | 4 | 2 |
| Auto Open/Close Lid | Yes (motion sensor) | Yes (motion sensor) |
| WASHLET+ Compatible | T20 & T40 systems | T40 system only |
| Auto-Flush Ready | Yes (kit sold separately) | Yes (kit sold separately) |
| Buy Now |  |
 |
1. TOTO WASHLET S7A (SW4736AT40#01)
The TOTO WASHLET S7A is the current flagship bidet seat from TOTO — the direct replacement for the beloved S550e and the most feature-complete seat in the WASHLET lineup outside of a fully integrated toilet system.
It takes everything that made the S550e great and refines it: a slimmer profile, expanded EWATER+ coverage, more user presets, and an updated remote that now works with both T20 and T40 WASHLET+ toilet systems.
Features
- Ultra-slim 4.06″ rear height — among the lowest of any bidet seat on the market
- Seamless seat design with no gap for dirt or moisture to collect
- EWATER+ electrolyzed water cleans the wand, the bowl, and the underside of the seat
- PREMIST wets the bowl before every use to prevent waste from adhering
- Auto open/close lid triggered by motion sensor as you approach and depart
- 4 user presets for personalized wash settings saved to the remote
- 5 spray settings with oscillating and pulsating modes
- Heated seat, warm air dryer, and power deodorizer with variable settings
- Auto-flush compatible with separately sold kit on select TOTO T20/T40 toilets
- Compatible with both T20 and T40 WASHLET+ toilet systems for concealed cord/hose installation
Pros
- The slimmest TOTO bidet seat available — creates a near-integrated look on any bowl
- EWATER+ now extends under the seat, a hygiene upgrade not found on the S550e
- 4 user presets is double the S550e — ideal for families and multi-user households
- Works with both older T40 and newer T20 WASHLET+ systems — more toilet compatibility
- Updated tactile remote buttons are easier to press than the previous touchpad design
Cons
- Significantly more expensive than the S550e — a meaningful price jump for incremental upgrades
- No LCD screen on the back of the remote, making advanced fine-tuning less intuitive
- Only available in elongated size as the primary format — round version (SW4735) sold separately
If you want the best seat TOTO currently makes, the S7A sets the new benchmark for personal hygiene, bathroom aesthetics, and hands-free automation.
It’s the natural next step for anyone who loved the S550e — and for anyone building a premium bathroom from scratch, it’s the seat to beat, especially when you pair it with a TOTO WASHLET+ compatible toilet from our TOTO AP vs EP wall-hung toilet guide.
Check its current price on Amazon
2. TOTO WASHLET S550e (SW3056#01)
The TOTO WASHLET S550e was, for several years, the answer to the question “what is the best bidet seat money can buy?” — and for good reason.
It delivers instantaneous warm water, full EWATER+ bowl and wand cleaning, auto open/close lid, a night light, and a slim-for-its-era design that set the standard the entire industry tried to match.
Features
- 4.81″ rear height (contemporary lid) — slim, though noticeably taller than the S7A
- EWATER+ covers wand and toilet bowl after every use
- PREMIST bowl wetting before each use prevents waste buildup
- Auto open/close lid and seat with proximity sensor
- Instantaneous water heating with no warm water time limit
- 5 spray settings with oscillating and pulsating modes
- 2 user presets saved to the remote control
- Heated seat, warm air dryer, built-in deodorizer, and night light
- Auto-flush compatible with separately sold kit on T40 WASHLET+ toilets
Pros
- Proven, highly reliable flagship model with years of positive user feedback
- Full EWATER+ bowl and wand cleaning — genuinely reduces the need for chemical scrubbing
- Touchpad remote with illuminated display is intuitive and familiar to current owners
- Clearance pricing on remaining stock makes it significantly more affordable than the S7A
- All core luxury features are present: heated seat, dryer, deodorizer, auto lid, night light
Cons
- Officially discontinued as of April 2025 — no manufacturer support going forward
- Only 2 user presets compared to the S7A’s 4 — a real limitation for multi-person households
- Taller rear profile (4.81″) makes it look less integrated than the ultra-slim S7A
- EWATER+ does not extend under the seat the way it does on the S7A
- T40 WASHLET+ only — does not support the newer T20 system
- Gap under the seat can trap dirt and is harder to clean than the S7A’s seamless design
If you can find the S550e at a deep discount and you’re a single-user or two-person household who doesn’t need the latest features, it remains an excellent performer.
That said, if you want long-term peace of mind and the most advanced TOTO hygiene technology available, the S7A is the smarter investment — as our guide to the highest-rated bidet toilets also reflects.
Check its current price on Amazon
Design & Profile: Slim vs. Slimmer
The S7A wins this category outright.
At 4.06″ in rear height versus the S550e’s 4.81″, the S7A sits nearly three-quarters of an inch lower on the bowl — a difference you’ll notice every time you walk into the room.
The S7A also eliminates the gap that ran along the underside of the S550e seat — the one that could collect moisture and grime and was notoriously tricky to clean.
Both seats offer contemporary and classic lid styles to match different toilet bowl profiles, but the S7A’s more rounded contemporary lid is a more refined update that blends cleanly with modern toilet designs.
If how your toilet looks matters as much as how it performs, the S7A is the clear winner here.
For more on pairing your WASHLET with the right toilet, our bidet toilet vs bidet seat comparison is a helpful place to start.
Winner: TOTO WASHLET S7A
Hygiene Technology: EWATER+ Coverage Is the Key Difference
Both seats use TOTO’s signature EWATER+ system, which electrically transforms tap water into a mild sanitizing agent.
Both also use PREMIST, which wets the bowl before every use so waste is far less likely to stick.
But the S7A goes further — it also uses EWATER+ to mist the underside of the seat, an area that the S550e left uncleaned.
In practice, this means the S7A passively maintains a cleaner toilet environment with even less manual intervention.
If you’re interested in this kind of low-effort bowl hygiene, our best self-cleaning bidets guide explores how TOTO’s approach compares to other systems on the market.
Winner: TOTO WASHLET S7A
User Presets & Remote Control: Family-Friendliness Matters
The S550e ships with a touchpad-style remote with 2 user presets — fine for solo use, tight for a couple, and limiting for a family.
The S7A gives you 4 user presets, meaning everyone in the household can save their preferred water temperature, pressure, spray mode, and dryer settings with one button tap.
The S7A’s remote switches to a horizontal layout with larger tactile buttons that are backlit for low-light use.
TOTO removed the LCD screen from the rear of the S7A remote (the S550e had one), which makes fine-tuning advanced settings slightly less intuitive.
For everyday use across multiple users, the S7A’s 4 presets is the more practical setup — and it’s one of the features that most clearly separates these two generations.
Our best heated bidet toilet seats guide dives deeper into how multi-user households should think about preset capacity when shopping for a seat.
Winner: TOTO WASHLET S7A
Compatibility & Installation: T20 vs. T40
Both seats are DIY-installable on most standard elongated toilets — attach the mounting plate, connect the T-valve to your existing water supply, and plug into a nearby GFCI outlet.
Where they differ is in WASHLET+ system compatibility.
The S550e works only with TOTO’s older T40 WASHLET+ toilets for concealed cord and hose installation.
The S7A works with both T20 and T40 systems — meaning it’s compatible with a broader range of current TOTO toilet models and is future-proofed for TOTO’s newest releases.
If you’re building a full bathroom setup around a TOTO toilet, that extra T20 compatibility with the S7A is a meaningful advantage.
You can explore more about WASHLET+ compatible wall-hung toilets in our TOTO AP vs EP guide.
Winner: TOTO WASHLET S7A
Value: Discontinued Stock vs. Current Generation
The S550e’s discontinuation is also its main value argument — remaining clearance stock can be found at significantly lower prices than the S7A.
If you find it at a meaningful discount, the S550e still delivers an elite bidet experience with all the core luxury features most people want.
But keep in mind: discontinued means no future manufacturer support, limited or no warranty from authorized sources, and no guarantee of replacement parts down the line.
The S7A commands a premium, but it’s the current flagship — actively sold, warranted, and supported.
For buyers who want long-term reliability without chasing clearance deals, the S7A is the safer bet.
Our best bidets for existing toilets guide can help you weigh the options at different price points if budget is a factor.
Winner: Tie — S550e on price, S7A on long-term value
Verdict — Which One Should You Buy?
Both seats are excellent.
But they’re excellent for different buyers.
Buy the TOTO WASHLET S7A if… you want the best TOTO bidet seat currently available, you have a multi-person household that will benefit from 4 user presets, you care about the slimmest possible profile, you want EWATER+ covering the underside of the seat, or you’re pairing the seat with a newer TOTO T20-compatible toilet.
Buy the TOTO WASHLET S550e if… you find remaining clearance stock at a substantially lower price and you’re a one or two-person household that doesn’t need the extra presets or expanded EWATER+ coverage — and you’re comfortable purchasing a discontinued product.
For most buyers, the S7A is the right call.
It represents a genuine step forward on every dimension that matters — design, hygiene, compatibility, and convenience — and it’s the seat you’ll still be happy with in five years.
If you want to see how the S7A compares against other seats in TOTO’s current lineup before committing, our TOTO C5 vs S7 comparison and the bidet toilet seat comparison chart are both excellent starting points.
FAQ
Is the TOTO S550e still available to buy?
The S550e was officially discontinued by TOTO in April 2025 and has been replaced by the TOTO WASHLET S7A.
Some remaining stock may still be available through third-party sellers at clearance pricing, but it is no longer a current product and is not backed by active manufacturer support.
If you’re buying new, the S7A is the recommended replacement.
What is the main difference between the S7A and the S550e?
The most meaningful differences are the S7A’s ultra-slim 4.06″ profile (vs. 4.81″ on the S550e), its 4 user presets (vs. 2), its expanded EWATER+ coverage that now includes the underside of the seat, its seamless seat design, and its compatibility with both T20 and T40 WASHLET+ toilet systems.
The core cleaning experience — instantaneous warm water, PREMIST, EWATER+ wand and bowl cleaning, auto lid, heated seat, dryer, and deodorizer — is shared by both.
Can I use the TOTO S7A on my existing toilet?
Yes — the S7A installs on most standard elongated toilets without any special plumbing.
You’ll attach the seat to the toilet bowl, connect the water supply via T-valve, and plug the unit into a GFCI outlet within reach.
If you own a compatible TOTO WASHLET+ toilet (T20 or T40 system), you can also conceal the cord and water line for a cleaner look.
Our guide on how bidet nozzles work is a helpful read if you’re new to electric bidet seats.
Is the S7A worth the extra cost over the S550e?
If you’re comparing full-retail prices and can find the S550e at a meaningful discount, the value gap narrows considerably — both seats deliver a premium TOTO experience.
But if you’re comparing at similar price points, or you’re a multi-person household, or you simply want the latest technology with active manufacturer support, the S7A is worth the premium.
For a broader look at how TOTO’s current lineup stacks up across price tiers, our Brondell Swash 1400 vs TOTO Washlet S5 comparison and the Brondell CL1700 vs TOTO S2 comparison show how TOTO competes at other price points too.
Conclusion
The TOTO WASHLET S7A vs S550e comparison comes down to one simple question: do you want the best seat TOTO currently makes, or are you looking to take advantage of remaining stock on a discontinued model?
The S550e was a legendary product.
But the S7A is better — slimmer, cleaner under the seat, more user-friendly for families, and more compatible with TOTO’s current toilet ecosystem.
If you’re ready to invest in a seat that will serve you well for years to come, the S7A is the one to get.
And if you’re still exploring your options, our bidet toilet seat comparison chart covers the full spectrum of what’s available — from entry-level seats all the way up to full integrated bidet toilet systems.
You can also learn more about day-to-day bidet use in our guides on whether you need to wipe before using a bidet and the best bidets with warm air dryers.
Whatever you choose, you’re upgrading your bathroom in a meaningful way — and you’ll wonder how you ever went without it.
