How to Install a Bidet Toilet Seat

Discover the difference between wiping and washing with a bidet toilet seat.

By
Timothy Dale
Timothy Dale

Timothy Dale is a home repair expert and writer with over a decade of hands-on construction and home improvement experience. He is skilled in residential, commercial, industrial and institutional plumbing, electrical, carpentry, installation, renovations, and project management.

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Published on 03/09/22
Reviewed by
Richard Epstein
Richard Epstein
Reviewed by Richard Epstein
Richard Epstein is a licensed master plumber with over 40 years experience in residential and commercial plumbing. He specializes in estimating as well as design and engineering for plumbing systems, and he works for one of New York's largest union plumbing construction companies.
Learn more about The Spruce's Review Board
Bidet toilet seat
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Project Overview
  • Working Time: 20 - 45 mins
  • Total Time: 30 mins - 1 hr
  • Skill Level: Beginner
  • Estimated Cost: $170 to $2,650

When toilet paper is running low and all you have left is a small stack of scratchy napkins that you know may clog the drain, the thought may pop into your mind that a bidet would solve all of your problems. However, many bathrooms aren't big enough to fit a toilet and a full-size bidet. Additionally, full-size bidets typically require a plumber to complete the installation, which can significantly increase the cost.

These thoughts often turn people away from the idea of installing a bidet at home, despite the benefit of enhanced cleanliness. To fill the gap between the desire for a bidet and the hesitation at the installation costs and bathroom layout challenges, bidet toilet seats have become a popular alternative. These devices mount directly to the toilet and attach to the toilet supply line with a T-valve, meaning that you don't need any extra space in the bathroom. Additionally, just about any DIYer can handle a simple bidet toilet seat installation where the necessary connections are already available, so you may not have to call in a plumber to get the job done.

Discover how to install a bidet toilet seat below, so you can feel truly clean after a visit to the bathroom.

Tip

This project can easily become more of a challenge (and not beginner-friendly) if the old toilet seat is difficult to remove or if plumbing or outlet modifications are friendly. To avoid any difficulties, ensure your bidet toilet seat of choice fits into your space (and onto your toilet) and that the necessary connections are available before beginning.

Why You Should Buy a Bidet

What You'll Need

Equipment / Tools

  • Screwdriver
  • Channel locks
  • Towel
  • Bucket

Materials

  • Bidet toilet seat kit
  • Lubricating spray

Instructions

  1. Remove the Old Toilet Seat

    In order to install the new bidet toilet seat, the old toilet seat will need to be removed. Inspect the nuts and bolts that are currently securing the old toilet seat to the toilet. Some toilet seat fasteners can be unscrewed by hand, but if the nuts are seized, then you may need to resort to using a lubricating solution, like WD40. A set of channel locks can also help to grip the nuts, while many toilet seat bolts have a slotted top where a screwdriver can be held to prevent the bolts from simply spinning in place.

    Once you loosen the fasteners that are securing the toilet seat to the toilet you should be able to lift the toilet seat off of the toilet. Take a few minutes to clean the toilet, especially around the bolt holes, so that the new bidet toilet seat can be fastened to a clean surface without grime, lubricating spray, or any other obstructions.

    Tip

    Keep in mind that some bidet toilet seats actually work with your existing toilet seat, so check the manufacturer's directions before throwing away the old toilet seat.

  2. Turn off the Water Supply to the Toilet

    After removing the old toilet seat and setting it aside, you will need to turn off the water supply to the toilet. Typically you can find an isolation valve behind the toilet. If you aren't sure about whether you are looking at the right valve, simply follow the supply hose from the bottom of the toilet tank to the water supply pipe in the wall. The valve to turn off the water supply attaches these two parts of the incoming water line.

    Turn off the water supply to the toilet with the isolation valve, then flush the toilet to drain any water that is remaining in the tank. After flushing, check the toilet tank to determine if it is filling with water or remaining empty. If the toilet is still filling with water even with the valve turned off, then it's likely that the valve doesn't work properly. In this case, you will need to turn off the main water supply valve for the home, then repeat the process of flushing the toilet to empty the remaining water from the tank.

  3. Attach the T-Valve to the Supply Line

    The toilet tank will likely still have some water remaining in the bottom, so lay a towel on the ground and position a bucket underneath the toilet where the water supply hose is connected. To install the bidet toilet seat, you will need to unscrew the toilet's supply hose from the toilet, then screw a T-valve into the bottom of the toilet when the supply hose was previously.

    What Is a T-Valve?

    A T-valve is a T-shaped plumbing part that is used to split the incoming water supply in order to provide water to both the toilet tank and the bidet toilet seat. Typically, this part comes with a bidet toilet seat kit. 

    With the T-valve attached to the toilet, the next step is to connect the toilet's supply hose to the T-valve. Tighten up the fittings, ensuring that the connections are secure so that there aren't any leaks when the water supply is turned back on. Don't connect the bidet toilet seat to the T-valve yet.

  4. Install the Bidet Toilet Seat

    The bidet toilet seat needs to be mounted to the toilet before you can continue. You should have already checked that your bidet toilet seat is the same shape as the toilet (many bidet seats don't fit round-front toilets, for example), but double-check this before proceeding.

    Most bidet toilet seat kits will include the necessary fasteners, as well as a mounting plate to secure the bidet toilet seat to the toilet. Position the mounting plate on the back of the toilet bowl, making sure to align the bolt holes accurately. A flat plastic mounting plate should come with your bidet seat.

    Put the included bolts through the bolts holes and hand-tighten the nuts to fasten the mounting plate to the toilet bowl. If you feel like the fasteners are not tight enough, then you can use a set of channel locks to snug up the connections.

    Slide the bidet toilet seat onto the mounting plate and push it toward the back of the toilet until you hear a click that indicates the bidet toilet seat is locked in place.

  5. Connect the Bidet Toilet Seat to the Water Supply

    With the bidet toilet seat safely secured to the toilet, you can go ahead and attach the water supply hose from the bidet toilet seat to the open end of the T-valve. Also, make sure that the other end of the bidet water supply hose is properly connected to the bidet toilet seat.

    Double-check all of the connections and tighten them with your channel locks if necessary. Keep the bucket and towel in place to make sure that there won't be a huge mess if there are any leaks when you turn the water on.

  6. Test for Leaks

    Turn the water on either at the isolation valve on the toilet water supply line or, if you had problems turning the water off with the isolation valve, using the main water shut-off. Check all connections for any sign of a leak.

    If your bidet has functions that require electricity, like heated water or a drying mode, then you need to make sure that it's plugged into a grounded GFCI outlet. You should have an outlet within reach inside the bathroom; if you don't, do not use an extension cord. It may be better to opt for a non-electric bidet or have a new outlet installed by a professional electrician.

  7. Verify the Functions Are Working

    The final step in the process is to test out the features of the new bidet toilet seat. Each product will have a different set of functions, which is why the cost of a bidet toilet seat can range significantly from $170 to more than $2,000 for luxury products.

    It should be mentioned that most bidet toilet seats only work if you actually sit on the seat or trigger the sensor to trick the seat into thinking that it is currently occupied. This feature is designed to prevent accidental spraying when the bidet toilet seat is not in use.