Shop for a TOTO toilet and you'll keep meeting a cryptic suffix: T40. Drake models with it, Aquia IV models with it, washlet seats "for WASHLET+ toilets." It's the key to the cleanest bidet-seat installation you can get — and knowing what it means before you buy saves you from the two most common regrets: paying for a connection you'll never use, or wishing you had it after the toilet is bolted down.
The problem WASHLET+ solves
A bidet seat needs two things a normal toilet doesn't provide: water and electricity. On a standard install, the water tee and hose sit visibly beside the tank and the power cord drapes to the nearest outlet. It works fine — millions are installed this way — but it looks like an add-on.
WASHLET+ is TOTO's concealed-connection system. On a WASHLET+ toilet, a channel in the ceramic routes the seat's water line and cord through the toilet body, invisible from any angle. The finished result looks like a single integrated smart toilet at a fraction of the price of one.
How to read the model numbers
- "T40" in a toilet model (e.g. Drake bowls and complete toilets marked T40) means the ceramic has the concealed routing channel. The toilet works perfectly with an ordinary seat too — the channel just sits unused.
- "T40" or "AT40" in a seat model (e.g. WASHLET S7 SW4726AT40) means the seat ships with the hardware for concealed hookup on a WASHLET+ toilet — and adapts to a standard exposed install on any other toilet.
- The SS124 SoftClose seat is the regular (non-bidet) seat shaped to pair with WASHLET+ toilets, if you want the toilet now and the washlet later.
The smart way to plan it
The T40 version of a toilet usually costs the same or barely more than the standard one. So the practical advice is simple: if there is any chance you'll ever add a washlet, buy the WASHLET+ version of the toilet now. The connection costs nothing to leave dormant, and it can't be added to a non-T40 toilet later. Run a GFCI outlet behind the toilet during the same renovation and future-you inherits a ten-minute upgrade instead of a project.
Pairings people actually buy: a Drake or Aquia IV WASHLET+ toilet with the WASHLET S5 (best value) or the S7/S7A for EWATER+ bowl misting — our S5 vs S7 vs S7A comparison breaks down that choice.
What WASHLET+ is not
- It's not required to use a bidet seat — any elongated TOTO washlet fits any elongated toilet, exposed hoses and all.
- It's not an integrated smart toilet — those (like TOTO's G5A and NEOREST lines) build the washlet into the fixture permanently, at a much higher price. WASHLET+ gives you most of that look with replaceable, upgradeable parts.
- It's not brand-agnostic — the concealed routing is TOTO-to-TOTO. Other brands' seats won't use the channel.
Frequently asked questions
Can I put a regular seat on a WASHLET+ toilet?
Yes — any standard elongated seat fits, and TOTO's SS124 SoftClose is shaped to cover the connection area neatly.
Can the channel be retrofitted to my current toilet?
No. The routing is cast into the ceramic. That's exactly why it's worth buying the T40 version up front.
Does WASHLET+ affect flushing or warranty?
No — the T40 and non-T40 versions flush identically and carry the same warranty. The only difference is the concealed channel.
Which outlet do I need?
A grounded 15A GFCI outlet behind or beside the toilet. On WASHLET+ installs the cord exits low and stays hidden, so place the outlet low on the wall.