How to Install a Bidet Seat
Part of our Toilets & Bidets guides.
Bidet attachments and seats connect to the toilet's cold supply with a T-valve. Turn off the water (and power at the breaker for anything electrical) before starting, and follow the product manual where it differs from these general steps.
| Time | 30-60 minutes |
|---|---|
| Difficulty | Easy |
| Tools | Adjustable wrench, towel, screwdriver |
Step by step
- Shut off and flush. Close the toilet's supply valve and flush to empty the tank.
- Remove the seat. Unscrew the seat bolts under the bowl.
- Install T-valve. Disconnect the tank supply line, add the T-valve, reconnect.
- Mount plate or attachment. Place the attachment or seat plate over the bolt holes and refit the seat or bolts.
- Connect hose. Connect the bidet hose to the T-valve.
- Power (electric seats). Plug into a grounded GFCI outlet; no extension cords.
- Test. Open the valve slowly, check for drips and test each wash mode.
Tips & common mistakes
- Check bowl shape (round vs elongated) before buying.
- Keep the hose clear of the floor for cleaning.
Check compatibility first
- Bowl shape: round vs elongated must match.
- Bolt spacing: most US toilets have 5.5 inches between seat bolts.
- Supply line: most use a 3/8-inch compression connection at the tank; the T-valve splits it.
- Skirted or one-piece toilets may hide the bolts or have an unusual tank shape; check the bidet's compatibility notes.
Leak-free connections
Hand-tighten plastic fittings, then add a small turn with a wrench. Overtightening can crack them. Most T-valves seal with rubber washers, so plumber's tape isn't needed on those threads (and can cause leaks if it bunches). Open the supply slowly and watch every joint for a few minutes with a dry paper towel.
Electric seats: outlet and cord
The seat needs a grounded outlet within reach of its cord. If you need a new outlet, have an electrician install a GFCI receptacle near the toilet; it's a common, quick job.
After installation
Run each wash mode for a few seconds aimed into the bowl to flush air from the line. Adjust nozzle position and pressure for comfort. Clean nozzles monthly, or use the self-clean function if your seat has one.
Frequently asked questions
Do bidets work with all toilets?
Most two-piece toilets; some one-piece and skirted toilets need specific models.
How long does a bidet seat take to install?
Usually 30-60 minutes.
Do I need tools?
An adjustable wrench and screwdriver are typically enough.
Can a bidet seat damage my toilet?
Not if installed correctly; avoid overtightening bolts.
What if my toilet has no shut-off valve?
Install one before connecting the bidet; it's good practice anyway.