replacing toilet seat on a fully skirted toto

Tips on Replacing Toilet Seat on a Fully Skirted Toto

In this article we will discuss issues on replacing toilet seat on a fully skirted toto. The skirted design conceals the trap way under the base and the fill valve under the tank giving it a polished modern look, which arises two challenges.

First the fill valve under the tank of the skirted toilet may be inaccessible or too cramped to allow the t-valve of the new toilet seat. Two, the accompanying hardware of your new or bidet toilet seat may have compatibility problems.

You may need to purchase additional parts like a T- connector to attach to the shut off valve at the back of the toilet instead of the fill valve.Two, get a hose extension to make the fill valve accessible or purchase compatible bolts to complete installation of the toilet seat.

Challenges of replacing toilet seat on a fully skirted toto

Inaccessible Fill Valve

For standard toilets the fill valve is usually underneath the toilet tank, but for a fully skirted toto the fill valve is concealed at the back of the toilet and is inaccessible because it could be too close to the wall.

If your a replacing with a bidet toilet seat , it comes with a ⅞ inch t- connector or water splitter to fix underneath the tank and provide the water needed for your bidet. 

In this case it will be too cramped and you will need to get an alternative connector to fix to the shut off valve instead of the fill valve.

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Unconventional mounting bolts

Another common challenge when replacing a toilet seat on a fully skirted toilet is their unconventional bolts. A regular 2 piece toilet seat is attached to the toilet bowl from underneath with plastic bolts that can be tightened or loosened with nuts.

Whereas a fully skirted toilet seat is attached from the top of the toilet seat using bolts that are covered with plastic sleeves.

And because most replacing toilet seats come with conventional plastic bolts and nuts you will experience an issue and will need to get compatible mounting bolts for the seat.

Solutions to replacing toilet seat on a fully skirted toto

Use an alternative t valve

The easiest method is to use a t- valve which attaches to the shut off valve instead of the toilet fill valve underneath the tank. In that case you get a t valve specifically for skirted toilets. 

It has 3 connections, one at the top and another at the bottom with ⅜ inch threads that perfectly fit shut off valves. And a third one ½ inch  pipe thread for connection to bidets if you’re replacing it with a bidet toilet seat.

All you have to do is install the t valve between the shut off valve and your water supply hose. For shut off valves which are ½ inch you must get one that fits that specifically.

If you are replacing it with a toto washlet please note that  it will not be compatible because of the different hose design and will need an additional adapter THP3141 for it to be completely compatible.

In that case the easiest method will be to use the extension hose method instead.

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Use an extension hose

This is the method we recommend for the toto wash lets because it will allow you to use the original t- valves. The extension hose will be connected  to the fill valve of your skirted toilet at the back and hence extending  the ⅞ inch connection.

In this case you will need to disconnect your current water supply hose and instead use the new extension hose then fix the t-valve which comes along with it. One side will connect to the end of the extension hose and the other side to the bottom of the original supply hose.

This extension hose method will work well for hand held sprayer bidets and non electric bidet attachments that use the ⅞ inch t- valves.

See also How to protect your bathroom floor from urine 

Compatible top mounting bolts

When replacing the toilet seat for a fully skirted toto, you may face mounting problems with the plastic bolts and nuts that come with the new toilet seat. In that case you will need to get replacement bolts to tighten the seat to the bowl. 

You will need to get the old bolts out. If they are a little tight, use a screwdriver on the bottom and press upwards to loosen it a little. Then you place the rubber slides to the toilet bowl mounting hose and tighten them from above with a screwdriver.

However if your skirted toto is already using top mounting bolts you won’t need to replace them.

See also Why is there urine around toilet base?


When replacing toilet seat on a fully skirted toto you may face a number of problems depending on the design of the new toilet seat. First the fill valve may be inaccessible if you are replacing it with a bidet toilet seat. To make the installation easier, you can get an extension hose to allow you to use the original t valves.

For mounting problems you will have to use replacement bolts that will fix the toilet seat securely to the bowl. However, if you have top mounting bolts that won’t be necessary.

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