TOTO Part

TOTO + Bidet Integration

How to add bidet functionality to a TOTO toilet — covers the Washlet seat line (S550e, C5, K300, S350e), pre-engineered Washlet+ Drake combinations, third-party bidet seats that fit TOTO bowls, and the install reality (T-adapter + GFCI outlet).

Updated May 2026 · TOTO Toilets

"TOTO toilet with bidet" is a search that splits into two distinct products: a TOTO toilet bowl with a TOTO Washlet seat (the modular path — buy a Drake bowl, add a Washlet seat later), or a TOTO Washlet+ integrated combo (pre-engineered as a unit — Drake bowl + Washlet S550e ships as one product). Both work; the modular path is cheaper and more flexible. Here's how to choose and what's involved in the install.

The two integration paths

Path 1: Modular — bowl + separate Washlet seat

Start with a TOTO bowl (Drake, Drake II, Vespin II, Aquia IV, UltraMax II are all Washlet-compatible). Add a TOTO Washlet seat to it. The seat clips onto the same bowl mounting bolts as a standard SoftClose seat. Total cost: $400 (bowl) + $700–$1,500 (Washlet seat) = $1,100–$1,900.

  • Pros: Cheaper. You can upgrade later (start with a basic seat, add Washlet when budget allows). You can replace the Washlet without changing the bowl if technology changes.
  • Cons: Two products to coordinate. The seat-bowl gap is slightly visible (vs the seamless look of an integrated combo).

Path 2: Pre-engineered Washlet+ Drake combo

TOTO sells the Drake II bowl + Washlet+ S550e seat as a single product ($2,400–$2,900). The Washlet+ designation means the seat is pre-tuned to the bowl's geometry — the spray nozzle hits the correct position, the auto-flush is calibrated to the Drake II's flush valve.

  • Pros: Single SKU, single warranty, optimized fit. Looks slightly cleaner than the modular path.
  • Cons: More expensive. Locked into the specific Drake-Washlet pairing.

Which TOTO Washlet seat to choose

Washlet modelPriceHeated seatHeated washAir dryerAuto open/close lidBest for
S550e Classic / Contemporary$1,400–$1,700✓ (instant)Premium home, master bath
S350e$1,200✓ (instant)Premium without auto-lid
C5$700✓ (tank-heated)Mid-tier value
K300$650✓ (tank-heated)Entry tier
A2$400✓ (tank-heated)Budget
B100$320✓ (cold water!)Cold-water-only — not recommended for cold-climate US

TOTO bowls compatible with Washlet

Almost every current TOTO residential bowl accepts a Washlet seat. The bolt pattern and inside-bowl geometry are standardized. Confirmed compatible:

  • Drake (elongated) — Washlet C5, K300, A2, S350e, S550e
  • Drake II — Washlet C5, K300, S350e, S550e (Washlet+ version preferred for S550e)
  • Vespin II — Washlet C5, K300, S350e, S550e
  • Aquia IV — Washlet C5, K300, S350e (S550e fits but with slight overhang; verify before ordering)
  • UltraMax II — Washlet C5, K300, S350e, S550e
  • Eco Drake / Eco UltraMax — Washlet C5, K300, A2 (S550e and S350e may have height clearance issues — verify)
  • Carlyle II — Washlet C5, K300 (S550e and S350e usually too tall for the low-silhouette Carlyle)
  • Neorest series — no Washlet needed; integrated equivalent is built-in

The install requirements (the gotchas)

  1. GFCI outlet within 3 feet. The biggest install gotcha. Most US bathrooms don't have an outlet near the toilet. Adding one requires an electrician — $150–$450 depending on access.
  2. T-adapter on water supply line. The Washlet needs a water connection. A 3/8" compression-fit T-adapter installs between the angle stop and the tank fill — the T splits flow into two outputs: one continues to the tank, one feeds the Washlet wash. TOTO ships this T-adapter with the Washlet seat.
  3. Existing seat removal. Lift the seat bolt caps, unscrew, remove old seat. Washlet seat clips into a mounting bracket that bolts to the same bowl holes.
  4. Cord routing. The Washlet's power cord runs ~5 feet from the seat to the wall outlet. Plan where the cord will route — most installs have the outlet directly behind the toilet.

Third-party bidet seats that fit TOTO bowls

If you don't want a TOTO Washlet but still want bidet functionality on a TOTO bowl, several universal-fit electronic bidet seats work:

  • Brondell Swash 1400 ($400–$580) — fits TOTO Drake II elongated. Comparable feature set to Washlet C5 at lower price.
  • Bio Bidet BB-2000 Bliss ($480) — fits TOTO elongated bowls. Strong feature set; less polished UI than Washlet.
  • Omigo Element+ ($380–$520) — direct-to-consumer alternative. Heated seat, wash, dryer.
  • Kohler PureWash ($240–$520) — Kohler-branded universal-fit bidet seat. Fits TOTO bowls.

For a complete bidet category — including standalone bidet attachments and bidet-only fixtures — see our bidet category.

Why so many people search for this

The cluster "toto toilet with bidet," "bidet toilet seat for toto toilet," "toto toilet and washlet" — total ~10k monthly US searches — reflects a specific buyer journey: someone already owns or is buying a TOTO toilet, and they want to upgrade to bidet functionality. The TOTO + Washlet path is the cleanest answer because TOTO designs the Washlet seats specifically for TOTO bowl geometry. Third-party bidet seats fit but won't be as well-integrated.

Cost summary for the modular upgrade

  • Existing TOTO toilet: already owned (or $400 for Drake elongated)
  • TOTO Washlet C5 seat: $700
  • T-adapter (included with Washlet): $0
  • GFCI outlet (if not present): $150–$450 by electrician
  • DIY install time: 30–60 minutes once GFCI is in place
  • Total upgrade (existing bowl): $700–$1,150
  • Total upgrade (new bowl + seat): $1,100–$1,600