Bidet Toilet Seats: Will One Fit, How to Install It, and Which to Buy

A bidet seat turns the toilet you already have into a bidet. No new toilet, and for most homes, no plumber. The two things to check first are whether it fits your bowl and whether there is an outlet within reach.

By Household Plumbing, 310 Adelaide St S, London  |  8 minute read

A bidet seat replaces your regular toilet seat. It bolts on in the same two holes, takes water from the same supply line that fills your tank, and washes you with a small nozzle that slides out from under the seat. Most electric models also warm the seat and the water, and some dry you afterward.

Before you order one, there are two questions that decide which seat you can use. This post walks through both, then how to install it, then which one to buy.

Bidet seat, bidet attachment or smart toilet?

• Non-electric bidet seat. A full seat and lid with a spray built in, run by your water pressure and a side handle. No outlet needed. The water is the same temperature as the cold supply to your toilet.
• Electric bidet seat. The most popular choice. Warm water, a heated seat, and on most models a warm air dryer, a deodorizer and a night light. Needs an outlet.
• Smart toilet. The bidet is built into the toilet itself, with features like an automatic lid and automatic flush. The cleanest look, and the biggest job, because the whole toilet is replaced.

You will also see bidet attachments, a spray bar that sits under your existing seat. They are the cheapest option, but you keep your old seat and get none of the comfort features. This post is about seats.

Will a bidet seat fit your toilet?

Toilet bowls come in two shapes, and the seat has to match.

• Elongated: an oval bowl, about 18-1/2 inches from the seat bolt holes to the front edge of the bowl.
• Round: a shorter bowl, about 16-1/2 inches from the bolt holes to the front.

Lift your seat and measure from the centre of the two bolt holes to the front edge of the rim. Most bidet seats, including most of the ones we carry, are made for elongated bowls, and the product page says so. If your toilet is round, TOTO and Moen make round versions of some of their seats, though not every model. Call us with your toilet's model number before you order and we will tell you what fits. Do the same if you have a one-piece toilet with an unusual shape around the back.

Check the space behind the seat too. The back of a bidet seat is deeper than a regular seat because the controls and water heater sit there, so it needs the tank lid and the wall to leave it room.

The outlet question most people miss

An electric bidet seat plugs into the wall, and its cord is short. TOTO tells you to plug its WASHLET seats into a GFCI outlet within three feet of the toilet, and not to use an extension cord. American Standard says its electric SpaLet seats need a 120-volt GFCI circuit of their own. A GFCI outlet is the kind with TEST and RESET buttons.

Plenty of bathrooms have an outlet by the sink and nothing near the toilet. If that is yours, you have two choices:

• Go non-electric. The American Standard AquaWash Essentials, $128, needs no power at all.
• Add an outlet. Hire a licensed electrician to put one in near the toilet. It sits next to water, so it is worth doing properly.

How to install a bidet seat

The seat comes with what you need to connect it: a mounting plate, a hose, and a T-shaped adapter that splits your toilet's water supply between the tank and the seat. Use the parts in the box. You will want an adjustable wrench, a towel, and a small bucket or bowl.

1. Turn off the water at the toilet. The shut-off valve is on the wall or floor behind the toilet. Turn it clockwise until it stops, then flush to empty the tank. Lay the towel under the valve.
2. Take the old seat off. Undo the two nuts under the back of the bowl, or the bolt caps on top, and lift the seat away. Clean the area while it is off.
3. Fit the mounting plate. Bolt the plate that came with the seat over the two holes. Centre it and snug the bolts.
4. Slide the seat on. Push it onto the plate until it clicks. Most seats can be popped off again with a button, which makes cleaning easier.
5. Add the T-adapter. Unscrew the supply line from the bottom of the tank, put the T-adapter in between, and reconnect. TOTO's rule is useful for any brand: a brass fitting gets a gentle turn with the wrench, a plastic one is hand tight only.
6. Connect the seat hose. Run the seat's hose from the open side of the T to the inlet on the side of the seat. Keep it free of kinks.
7. Turn the water on slowly and check every joint. Let the tank fill, look for drips at the T, the tank and the seat, and give a joint a little more snug if it weeps.
8. Plug it in and try it. Electric seats usually run a short self-clean the first time. Read the quick guide for the settings.

If the shut-off valve behind your toilet will not turn, or drips when you touch it, stop there. An old valve that will not close is a plumbing job, and forcing it can break it.

Rather not do it yourself, or found a valve that will not budge? Our plumbers install bidet seats. Call us at 519-438-1121 to book.

Which features are worth paying for

• Warm water. The biggest difference between a $128 seat and a $700 one. Every electric seat here has it. The TOTO WASHLET seats heat it on demand, so it does not run cold partway through.
• Heated seat. On every electric seat we carry. In a London January, you will use it.
• Self-cleaning nozzles. Standard on all of them. The nozzle rinses itself before and after each use.
• Warm air dryer. Cuts down on toilet paper. On the TOTO S2 and up, the Moen 5-Series and the American Standard 2.5 and 3.0.
• Remote or side panel. A side panel is simple and never goes missing. A remote is easier to reach and, on the TOTO S5, saves settings for up to four people.
• Nice to have: deodorizer, night light, a bowl pre-mist that helps keep the bowl cleaner, and on the TOTO S7A, a lid that opens and closes on its own.

Which bidet seat to buy

These are the ones we would point you to, by what you need. Bidet seats are ordered in for you. TOTO seats are the quickest to get, usually about a week, because our TOTO shipment comes in every Wednesday. Other brands usually take 2 to 4 weeks.

Want to see one before you order? We have several bidet seats on display in our showroom at 310 Adelaide St S, so you can see the size and the controls in person.

Want the bidet built in?

If the toilet itself is due for replacing, a smart toilet puts the bidet, the seat and the toilet in one piece, with no hose or seat edge showing. We carry three: the StoneTouch iKleen2 at $1,996, the TOTO WASHLET G5A at $4,199, and the American Standard Advanced Clean 100 at $4,473. The TOTO G5A has a manual flush backup, so it still flushes in a power outage.

How to use a bidet seat

Sit as you normally would, all the way back. Press rear wash or front wash, and start with the pressure and temperature on low. You can turn them up from there. When you are done, press stop, then use the dryer if your seat has one, or pat dry with a little paper.

Household Plumbing is family owned, BBB accredited with an A+ rating since 1986, and has served London since 1972.