The TOTO Washlet KS6 is worth $699 if you have an elongated toilet and want TOTO’s full mid-range hygiene package (endless warm water, EWATER+, PREMIST, a deodorizer and four user presets) in a slimmer-looking seat. For most households with an elongated bowl, I’d buy the KS6 at around $699, because it matches the S5’s feature list at the low end of that seat’s price range and adds four presets and a night light over the K300 I tested.
I haven’t tested the KS6 myself. I have tested the TOTO C5 and K300, and I owned an S550e, so I know how TOTO’s mid-tier seats behave in a real bathroom. Everything below on the KS6 comes from TOTO’s spec sheet and manual, the Bidet King listing, and that hands-on background.
The tricky part is that the KS6 and S5 look almost identical on paper. If you can work out which small differences apply to your toilet, you can save money or avoid a seat that won’t fit.
TOTO Washlet KS6 Review: Quick Summary Table
The washlet KS6 (model SW3946) is a premium bidet seat with almost every feature TOTO puts in its mid-range lineup, sold at about $699.
| Spec | TOTO Washlet KS6 (SW3946) |
|---|---|
| Price | About $699 |
| Shape and color | Elongated only, Cotton White |
| Water heating | Instantaneous, endless warm water |
| Water temperature | 95 to 104°F |
| Spray flow | 0.07 to 0.11 gal/min rear, 0.08 to 0.11 front |
| Spray modes | Aerated front and rear, oscillating, pulsating |
| Heated seat | 82 to 97°F |
| Dryer | 95 to 140°F, 3 settings, 8.83 cfm |
| Hygiene tech | EWATER+, PREMIST, CLEAN RESIN, deodorizer |
| Controls | Wireless remote, 4 user presets, docking station |
| Extras | Seamless seat, SoftClose, nightlight, auto energy saver |
| Power | 1,278 W rated, 1,435 W max |
| Cord length | 3.93 ft |
| Shipping weight | 15.3 lbs |
| Warranty | One-year limited |
What I like: endless warm water, four presets for shared bathrooms, and the full hygiene suite at a mid-range price.
What gives me pause: elongated and white only, a short power cord, and a one-year warranty on a $699 electronic bidet toilet seat.
What Is the KS6 and How Is It Different from the S5?
The KS6 is TOTO’s online-exclusive mid-range Washlet and the replacement for the K300, and it shares nearly all of its working parts with the S5. The real differences come down to lid styling, shape and color choices, and where you can buy it.
What Does TOTO Confirm About the KS6?
According to TOTO, the KS6 includes:
- Instantaneous water heating with warm water on demand
- A heated seat, warm air dryer and automatic deodorizer
- CLEAN RESIN, which TOTO says keeps the wand and seat cleaner and easier to maintain
- A multifunction remote with personalized memory for up to four users
- WASHLET+ compatibility, since TOTO includes it in its WASHLET+ set offers with one-piece WASHLET+ toilets
TOTO also positions the KS6 as an online-exclusive model. The S5 is the toto washlet sold both online and through showrooms.
TOTO’s KS6 manual covers model SW3946 and also lists the KS5 (SW3216). That tells me the two share a platform. The KS6 adds EWATER+ and PREMIST on top.
Which Differences from the S5 Remain Unclear?
Here’s what retailers and owners report, which I haven’t seen TOTO spell out side by side:
- Lid design. The KS6 has a more contoured, beveled lid that makes it look slimmer. The washlet S5 uses a lipped lid that covers the seat when closed.
- Front thickness. Bidet King lists the KS6 at about 1.3 inches at the front versus about 1.5 inches for the S5. I’d treat that as retailer data.
- Rear height. Both are reported at 5.5 inches.
- Shape and color. The toto washlet s5 comes in elongated white, elongated beige and round white. The KS6 is elongated Cotton White only.
I can’t confirm any difference in wash performance between the two bidet seats. TOTO’s materials don’t show one, so I wouldn’t pay extra for either one expecting a better wash.
Cleansing Performance
The KS6 gives you more ways to tune the spray than the K300 did, mainly because the spray position is now adjustable in every wash mode. The published flow rates are modest, so comfort comes from aeration and motion more than raw force.
What Spray Adjustments Does the KS6 Offer?
Bidet King lists these controls:
- Front and rear wash, both aerated
- Adjustable spray position, so you can move the wand forward or back
- Oscillating spray, which sweeps the wand back and forth
- Pulsating spray, which alternates between strong and soft pressure
- Water temperature from 95 to 104°F
- Water pressure, adjustable from the remote
The adjustable spray position is a bigger deal than it sounds for personal hygiene. On a seat without it, a taller or shorter person ends up shifting around to get the spray in the right place.
Oscillation was the feature I used most on the K300. Owners of the KS6 say the same about it here, and that matches my experience: it covers more area per wash.
What Can Specifications Tell Us About Wash Comfort?
The rear spray runs 0.07 to 0.11 gallons per minute, and the front runs 0.08 to 0.11. Those are low numbers. TOTO aerates the water, mixing in air so a small amount of water feels fuller.
On the K300, that aerated spray felt soft and broad. If you’re used to a strong, narrow jet from a non-electric attachment, the first few uses will feel gentler.
Your home’s water pressure affects this too. If the spray feels weak after install, my guide on bidet water pressure too low covers the usual fixes, such as a partly closed supply valve or a clogged filter.
Hot Water Performance
Hot water is the KS6’s strongest point: it heats water as it flows, so the warm spray doesn’t run out partway through a wash. That’s the same approach TOTO used on the K300 and C5.
How Does Instantaneous Heating Work?
Instantaneous water heating passes cold supply water through a heating element right as you start the wash. There’s no stored tank of warm water to drain.
That’s where the 1,278 W rating comes from. Heating moving water fast takes a lot of power for short bursts.
You set the temperature between 95 and 104°F. On the K300 I tested, the water hit a steady temperature within a few seconds and stayed there for the whole cycle, including back-to-back uses.
If you want the full mechanics, my explainer on how warm water bidets work covers tank and tankless designs.
How Does It Compare with the C5’s Tank?
I need to correct a common mix-up. The C5 I tested didn’t use a tank. It heated water on demand too, which is why its warm water lasted through long washes.
So if you’re coming from a C5, the KS6 doesn’t give you better hot water. You get the same endless supply, plus newer extras like four presets and CLEAN RESIN. My TOTO C5 Washlet review has my notes on that seat.
Tank-style seats work differently. The TOTO C100 Washlet stores warm water in a reservoir, so a long wash can turn cool once the tank empties.
If endless warm water is your top priority, I’ve rounded up the best bidet seats with tankless water heaters.
Design and Dimensions
The KS6’s design goal is to look slimmer than a typical electronic seat, through a contoured lid and a seamless seat. The dimensions that affect comfort, though, are close to the S5’s.
What Does the Seamless Seat Change?
A seamless seat design means fewer joints and gaps where grime collects. On older seats, including my S550e, the seam where the seat meets the housing was always the spot I had to scrub with a toothbrush.
The KS6 pairs that with clean resin coating. According to TOTO, CLEAN RESIN keeps both the wand and seat cleaner and easier to maintain.
In practical terms, that should mean wiping more often and scrubbing less. I can’t put a number on the time saved, since TOTO doesn’t publish one.
The SoftClose lid and seat lower slowly, which prevents slams. A release button on the right side lets you pop the seat off its mount for cleaning underneath.
Which Dimensions Should Buyers Verify?
These are the figures I’d check before ordering:
| Dimension | Reported figure | Source type |
|---|---|---|
| Rear height | About 5.5 in | Retailer and owner reports |
| Front thickness | About 1.3 in | Retailer |
| Seat opening (elongated) | 11 13/16 x 7 7/8 in | Retailer and owner reports |
| Power cord | 3.93 ft | Bidet King spec |
The 5.5-inch rear height is about 5/16 inch taller than the K300’s. Some owners of taller seats say they feel slightly more cramped than on the slimmer S7, so if you’re a larger person, that’s worth weighing.
Check TOTO’s spec sheet for your exact toilet clearances, since I won’t guess at numbers TOTO hasn’t printed.
Fit and Installation
The KS6 fits elongated toilets only, and it needs a grounded outlet within about four feet of the left side of the toilet. Most people can install it themselves in under an hour.
Will It Fit Your Toilet and Electrical Setup?
Run through this checklist before you buy:
- Bowl shape. Measure from the bolt holes to the front edge. Elongated toilets measure around 18.5 inches. Round bowls are shorter and won’t work with this seat.
- Outlet location. The cord is 3.93 feet. TOTO’s manual calls for a grounded outlet, and it warns that an ungrounded one creates a shock risk if something fails.
- Water supply. A T adapter splits your toilet’s supply line, so you need room near the shutoff valve.
- Tank clearance. Some one-piece toilets have curved tank bases that crowd the mount.
The install is the standard Washlet routine. You shut off the water, flush, swap the old seat for the mounting plate, slide the seat on until it clicks, and connect the T adapter.
If you haven’t done one before, my guide to installing a bidet walks through it, and my breakdown of what a bidet installation will cost you covers hiring an electrician for a new outlet.
Does WASHLET+ Compatibility Affect Your Choice?
WASHLET+ only matters if you own, or plan to buy, a one-piece TOTO WASHLET+ toilet. On those toilets, a second hole near the bolt holes lets the hose and cord run through the toilet, so they’re hidden.
On any other elongated toilet, the KS6 works like any heated bidet toilet seat. You’ll see the hose and cord on the left side, the same as with any other bidet seat.
TOTO also runs bundle discounts on WASHLET+ toilet and seat pairs, so if you’re replacing the toilet anyway, compare bundle pricing. My list of bidets for TOTO toilets covers other pairings.
Remote, Presets and Controls
The KS6’s illuminated wireless remote is the main reason I’d pick it over side-panel seats like the S2 in a shared bathroom. It’s double-sided, with daily controls on the front and setup controls on the back.
How Useful Are Four User Presets?
User memory presets save each person’s water temperature, pressure and spray position. One press and the seat runs that person’s wash.
On the K300, I had only two presets. With a family of four sharing one toilet, two slots meant constant re-tweaking. The KS6’s four slots cover most households.
Presets help most when people prefer very different settings. If one person likes a strong, cool wash and another wants a soft, warm one, presets save a lot of button pressing.
If you live alone, presets barely matter, and a cheaper seat with fixed controls will do the job.
What Can You Adjust from the Remote?
Bidet King’s walkthrough describes this layout:
Front of the remote:
- Rear wash, front wash and stop
- Dryer
- Spray position and pressure
- Four user preset buttons
Back of the remote:
- Water, seat and dryer temperature
- Nozzle cleaning
- Energy saving settings
The remote mounts on the wall in a docking station with a magnetic bracket. That keeps it from ending up in a drawer or behind the toilet, which happened with a remote I owned years ago. It runs on batteries, so keep spares in the bathroom cabinet.
EWATER+, PREMIST and the Deodorizer
These three features are what separate the KS6 from the cheaper KS5, and they cut down on how often you scrub. They don’t replace regular cleaning.
What Does Each Cleaning Feature Actually Do?
EWATER+ wand cleaning. The seat makes electrolyzed water from your tap water and uses it to rinse the wand after each use. Retailers report that the wand is cleaned inside and out. This is TOTO’s self-cleaning wand system.
PREMIST bowl misting. Before you sit, the seat mists the bowl with water. A wet surface makes it harder for waste to stick, so less residue clings to the bowl.
Automatic deodorizer. An air deodorizer pulls air through a filter on the right side of the seat while you’re seated.
On the K300, which has EWATER+ and PREMIST, I noticed fewer skid marks between cleanings and a cleaner wand when I pulled it out to check. I’d expect the same here, since TOTO uses the same systems.
For other seats with these features, see my roundup of the best self-cleaning bidets.
What Cleaning Will You Still Need to Do?
You’ll still need a regular cleaning routine:
- Bowl: scrub it as usual. PREMIST stretches the time between scrubs.
- Wand: extend it with the cleaning button and wipe it with a soft cloth every couple of weeks.
- Seat and lid: wipe with a mild cleaner. Skip harsh chemicals and abrasive pads on plastic.
- Deodorizer filter: check it and remove dust on the schedule in TOTO’s manual.
- Under the seat: pop it off the mount occasionally to clean the plate area.
My complete guide to cleaning a bidet covers which cleaners are safe for Washlet plastics.
Warm Air Dryer and Heated Seat
The heated seat is the comfort feature you’ll use every day. The warm air dryer is useful but slow, which is true of every bidet dryer I’ve tried.
What Are the Published Temperature Ranges?
| Feature | Range | Settings |
|---|---|---|
| Heated seat | 82 to 97°F | Adjustable from remote |
| Warm air dryer | 95 to 140°F | 3 settings |
| Dryer airflow | 8.83 cfm | Fixed |
| Water | 95 to 104°F | Adjustable from remote |
The seat range tops out a little below body temperature. On my S550e, the middle settings felt right for most of the year, and I bumped it up only in winter.
The dryer’s top setting of 140°F is hot enough that I’d start at the lowest setting and move up.
Which Comfort Features Matter Day to Day?
Heated seat. This is the feature owners mention most. Once you’re used to a warm seat, a cold one in a hotel bathroom comes as a shock.
Warm air dryer. On the K300 and C5, the dryer took a couple of minutes to fully dry. Most people I know use it for a short pass and then pat dry with a square or two of toilet paper.
Night light. The built-in LED lights the bowl at night, so you don’t have to switch on a bright overhead light. It’s new compared with the K300, and I’d use it in a hallway half bath.
Energy Use
TOTO publishes the KS6’s power draw at 1,278 W rated and 1,435 W maximum, but it doesn’t publish an annual kWh figure, so I won’t make one up.
What Do the Published Power Ratings Mean?
Those wattage figures describe the peak draw while the instantaneous heater runs at full output. A wash lasts under a minute, so the seat doesn’t pull that much power for long.
Between uses, the seat draws far less, mainly to keep the seat warm. Your real cost depends on:
- How many people use the toilet
- Your seat temperature setting
- How cold the bathroom gets
- Your local electricity rate
The peak draw matters more for wiring. A 1,435 W maximum on a circuit shared with a hair dryer can trip a breaker. If your bathroom outlet already handles a heater or styling tools, have an electrician check the circuit.
Can the Auto Energy Saver Help?
Yes. The auto energy saver learns when the toilet goes unused and lowers the seat temperature during those hours. It’s on the back of the remote.
On older seats, I left the seat heater running around the clock. A learning saver mode trims that standby heat during nights and workdays.
If the seat feels cold first thing in the morning, lower the energy saving level or turn the feature off. I’d leave it on for a guest bathroom that sits empty most of the week.
KS6 vs S5 vs K300
In a bidet toilet seat comparison of these three, the KS6 and S5 nearly tie on features, while the K300 falls behind on presets, cleaning and spray position.
Which Features and Prices Separate Them?
| KS6 | S5 | K300 | |
|---|---|---|---|
| Price | About $699 | About $668 to $780 | About $699 to $725 |
| Shapes | Elongated | Elongated, round | Elongated |
| Colors | Cotton White | White, Sedona Beige | White |
| User presets | 4 | 4 | 2 |
| Night light | Yes | Yes | No |
| Adjustable position | Yes | Yes | No |
The K300 was my preferred TOTO mid-range seat, and my TOTO K300 review explains why. TOTO has discontinued it, with the KS6 as its replacement, so stock is drying up.
Both the KS6 and S5 add CLEAN RESIN and the auto energy saver over the K300.
Who Should Buy Each Seat?
- KS6: buy it if you have an elongated white toilet and want four presets at around $699.
- S5: buy it if you have a round bowl or want Sedona Beige, or if you prefer the lipped lid look.
- K300: only if you find a leftover unit well below the KS6’s price. Otherwise, the KS6 adds features for about the same money. My TOTO K300 Washlet page has more detail.
If you’d rather spend less, the TOTO S2 uses a side panel instead of a remote. At the top end, the TOTO Washlet S7 runs about $1,223 and sits lower at the back. Outside TOTO, the Bio Bidet BB2000 is another remote-controlled seat worth comparing, and the Alpha JX2 (about $389) and Alpha UX Pearl (about $459) are cheaper picks.
TOTO Washlet KS6 Review: Conclusion
The KS6 is worth $699 for anyone with an elongated toilet who shares a bathroom and wants TOTO’s full hygiene suite. It matches the S5’s feature list, beats the K300 on presets and spray position, and keeps the endless warm water that made the K300 and C5 easy to live with.
Skip it if you have a round bowl or want beige, since the S5 covers those. Also plan around the 3.93-foot cord and the one-year warranty.
My one recommendation: buy the KS6 over a leftover K300 at the same price. Bidet King lists it at about $699. Before ordering, measure your bowl and confirm you have a grounded outlet within four feet of the left side of the toilet.
Ready to order? You can check current prices on the TOTO Washlet KS6 at Bidet King here (affiliate link). Bidet King handles TOTO warranty claims and support, which is why I buy there.