Will a TOTO WASHLET Fit Your Toilet? A Practical Compatibility Guide

Can you install a TOTO WASHLET on your existing toilet? In many cases, yes – even if your toilet is made by another brand. The key is to check the bowl shape, mounting holes, clearance behind the seat, and access to water and power before choosing a model.

Not sure which toilet you have? Email us your toilet model number and a few photos, and we'll help you check the options.

1. Is your toilet round or elongated?

Measure from the center of the two seat-mounting holes straight to the front edge of the porcelain bowl. You don't need to measure the existing seat, which can extend past the bowl.

• Elongated: approximately 18½ inches from the mounting holes to the front of the bowl.
• Round front: approximately 16½ inches from the mounting holes to the front of the bowl.

These are common reference measurements, not a guarantee of fit. Match the shape to the seat and check the full dimensional drawing for the particular model.

For example, the TOTO S5 SW3446#01 is elongated; the S5 SW3445#01 is round. They offer the same family of features, but they are made for different bowl shapes.

2. Measure the mounting holes

Measure from the center of one mounting hole to the center of the other. Standard North American toilets commonly have holes about 5½ inches apart, which is the reference spacing in TOTO's fit guidance. Unusual or proprietary mounting arrangements need a closer look. 

If the toilet has a skirted bowl or concealed hardware, check how the existing seat is removed and whether the WASHLET's mounting hardware can be installed. Don't assume that inaccessible nuts mean installation is impossible – the correct method depends on the toilet and seat.

3. Check the space between the holes and the tank

Measure from the center of the mounting holes back to the front face of the tank or any obstruction. The rear of the WASHLET needs room to sit flat and attach to its mounting plate.

As one example, TOTO's fit guidance specifies at least 2 inches for several elongated models, including the S7A, S7, C5 and C2. Requirements can differ by model and bowl shape, so use the dimensional requirements for the exact seat you're considering – especially if your measurement is close. 

A French-curve toilet – a one-piece design where the tank slopes forward into the bowl – can interfere with the seat housing even when the bowl length looks right. Some Kohler San Raphael and Santa Rosa configurations need particular care. Check the exact toilet model and dimensions; don't assume every version will fit or that every version is incompatible.

Also inspect the flat surface around the rear of the bowl. TOTO's general fit diagram calls for approximately 8 inches of open flat surface from the toilet centerline to the edge on each side for the models shown. Bowl contours and side controls can create additional restrictions. If the shape is unusual, send us a photo before ordering.

View the TOTO WASHLET fit and compatibility chart. This chart covers the models listed in it; for newer models or a seat not shown, check its current specification sheet or ask us for help.

4. Check the water supply and electrical outlet

Most electronic WASHLET installations connect to the toilet's cold-water supply using the seat's supplied connection hardware. Check that the shutoff valve and supply connection are accessible and compatible with the chosen model. A concealed or unusual supply may need additional parts or professional help.

You'll also need a properly grounded, GFCI-protected electrical outlet within reach of the WASHLET's power cord. Outlet location, cord length and electrical requirements vary by model. Have a qualified electrician install an appropriate outlet if needed, and follow the product's installation instructions and local electrical requirements.

Does the toilet need a hole for the WASHLET cord?

No – a standard WASHLET can often be installed on a compatible conventional toilet without a special hole in the bowl. Its cord and water hose remain visible outside the toilet.

WASHLET+ is TOTO's concealed connection system. A compatible WASHLET+ seat and toilet are designed to route the cord and hose through the toilet for a cleaner look. Check the specific seat and bowl pairing; matching the shape alone does not establish WASHLET+ compatibility. If you already own a conventional toilet, start by looking at a standard WASHLET and verify the fit.

Planning to replace the toilet too? The TOTO Drake MS776124CEFG#01 is a WASHLET+ ready elongated toilet that includes a SoftClose seat. A compatible WASHLET+ bidet seat is purchased separately. Check the individual product page and compatibility before pairing.

Will a WASHLET make my toilet flush automatically?

Not necessarily. Automatic lid operation and automatic flushing are separate features. Auto-flush requires a compatible WASHLET, such as the S7 or S7A, a compatible TOTO toilet and the correct auto-flush kit for that combination. Depending on the product, the kit may be included or sold separately. Confirm all components before ordering.

Which WASHLET should you choose?

Once you've confirmed fit, choose the features and controls you prefer:

• TOTO S2 elongated – a side-control option with instantaneous water heating. A round S2 is also available.
• TOTO S5 elongated – a remote-controlled option, also available in round.
• TOTO S7A WASHLET+ elongated – an option with automatic lid opening and closing for a compatible WASHLET+ toilet.

For a closer look at the features, read our TOTO WASHLET S2, S5 and S7 comparison.

What to send us for a compatibility check

Before you buy, email info@bath4all.com with:

• The toilet brand and model number, if you can find it – it may be stamped inside the tank or on the bowl.
• A photo of the entire toilet and a clear overhead photo of the area behind the seat.
• The bowl length, mounting-hole spacing and distance from the holes to the tank.
• The WASHLET model you're considering, plus a photo of the water shutoff if access is tight.

We'll help you narrow down the options and flag anything that needs a closer look. Bath4All is an authorized TOTO retailer, and we're happy to help before you order.