Installing a Bidet Toilet Seat on a Skirted Toilet: What Should I Know?


There are many kinds of toilets out in the market with many neat designs such as the popular “skirted” design. However, if you want to install a bidet toilet seat, this pretty design may become a bothersome headache. You will soon find that the fill valve of your skirted toilet may be inaccessible or too cramped to install a bidet seat’s t-valve. Also, the mounting hardware that comes with your bidet toilet seat may not be compatible. In this particular article, we’ll discuss the complications involved with installing a washlet seat on a skirted toilet and how to solve them.

What is a skirted toilet?

A skirted toilet is different from your regular toilet. A skirted toilet has a smooth skirt design that conceals the trapway at the base, as well as the fill valve under the tank giving the toilet an elegant look.  This design makes the toilet easier to clean and a nice modern appearance. Although the design is great to look at, it does present a few issues for installing a bidet toilet seat.


Skirted design toilet next to a non-skirted toilet

What are the problems with the skirted design?

Fill Valve

A typical 2 piece residential toilet will have its fill valve located underneath the toilet tank and easily accessible.  Bidet toilet seats usually come with a 7/8” t-valve that fits directly under the tank for its water supply. Skirted toilets tend to have the fill valve concealed behind the toilet, thus making it inaccessible.  There is often very little space between the back of the toilet and the wall.  For a bidet seat, the fill valve area is crucial because this is where you connect your t-valve (or water splitter) that supplies your bidet.

Mounting Bolts

Another issue with skirted toilets is that the mounting bolts for your toilet seat are not the same as your conventional 2 piece toilet. On a conventional toilet, the toilet seat is attached via plastic bolts that are tightened/loosened from underneath the bowl (near the trapway) with nuts.  But, with a skirted design things are done a bit differently.  The toilet seat is usually secured from above the bowl using screws that fit into sleeves.  Since most bidet toilet seats come with plastic bolts and nuts meant for conventional toilets, this presents a problem.

Luckily, has solutions for both of these issues.

What are the solutions to these pesky skirted toilet issues?

Alternative T-Valve for Skirted Toilets

The easiest solution to the fill valve issue is an alternative t-valve that can be installed on your shut-off valve instead of at your toilet's fill valve. Our t-valve for skirted toilets is designed to do just that. This t-valve has top male and bottom female connections that are 3/8" compression threads, making it a perfect fit for most shut-off valves. The third outlet is a ½” pipe thread that is compatible with most bidet seat hoses. If by chance your bathroom has a ½” shut-off valve, you will need our ½” t-valve instead. Simply install the skirted t-valve between your current toilet supply hose and the shut off valve on the wall.

However, please be aware that the skirted t-valve is NOT compatible with TOTO Washlets. For TOTO Washlets, you will need an additional adapter from TOTO (THP3141), or our extension hose for skirted toilets due to TOTO’s proprietary hose design. 

Click here for the skirted toilet t-valve package.

Extension Hose for Skirted Toilets

Another solution to the fill valve problem is a simple extension hose that connects to the fill valve of your skirted toilet and extends the 7/8" connection. The extension will allow you to connect the bidet seat's original t-valve to the end of the hose, instead of to the fill valve directly.  This is the preferred method for TOTO washlets due to their t-valve and hose design. 

To install, you would disconnect your existing supply hose from underneath the tank and install this hose instead.  The bidet seat's 7/8" t-valve will connect to the other end of this extension hose, and your existing supply hose will connect to the bottom of the t-valve. This hose can also be used for connecting hand held bidet sprayers or non-electric bidet attachments that use 7/8" t-valves.

Click here for the extension hose.

Extension Hose for skirted toilets 

Top Mounting Bolts

For the mounting issue, BidetKing carries top mounting hardware that can be tightened from above as opposed to below the bowl. The black rubber sleeves are inserted into the toilet bowl mounting holes, and the screws are then tightened with a screwdriver from above.  These would replace the plastic bolts/nuts that come with most bidet seats.

Note: in some instances, your skirted toilet may already be using top mounting bolts like these to fix your regular toilet seat.  In that case, you can just use what you have instead of purchasing these.

Click here for the top mounting bolts.

Top Mounting Bolts