There are three main types of bidet toilet seats. Non-electric attachments fit under your seat and spray room-temperature water. Dual-temperature attachments add a hot water line from the sink for a warm wash. Electric bidet seats replace your seat, heat the water and often the seat, and need a grounded GFCI outlet near the toilet.
What are the main types of bidet seats?
Most products fall into three groups. A fourth option, the standalone bidet fixture, is a separate plumbing fixture rather than a seat.
### Non-electric attachments (room-temperature water)
This is the simplest type. A thin attachment mounts between the toilet bowl and your existing seat, and a hose connects it to the toilet's cold water supply through a T-valve. Brondell's LES-10 is an example. Its manual lists an "Ambient temperature bidet wash," a "Durable braided metal cold water hose," and "No electricity or batteries required."
What you get: a spray at the temperature of your cold water, controlled by a knob or lever. What you don't get: warm water, a heated seat or a dryer.
### Dual-temperature attachments (a warm and cool wash)
These look much like non-electric attachments, but they add a second connection to your hot water. Brondell's SMB-25 dual-temperature model, for example, offers "Warm And Cool Water Bidet Washes" and "Adjustable Water Temperature," using hot water flex tubing.
The hot water comes from somewhere nearby. The SMB-25 manual says its hot water T-valve "will be installed at the hot water supply under your bathroom sink," and that this should be a 3/8-inch connection. So this type works best when the sink is close to the toilet and the tubing can reach it neatly.
### Electric bidet seats
An electric bidet seat replaces your toilet seat entirely. It heats the water itself and usually adds comfort features. Brondell's Swash installation guide lists an "Ergonomic Heated Seat," a "Warm Air Dryer" and adjustable water temperature and pressure.
Electric seats heat water in one of two ways:
- A small tank inside the seat. Kohler's installation guide for one model is titled "Toilet Seat with Bidet Functionality and Tank Water Heater."
- On-demand heating. Brondell describes the Swash's heater as an "instant ceramic heating system" that ensures "an endless warm water stream."
Both kinds connect to the cold water supply only. Kohler's guide says to "Connect only to cold water supply line carrying water of drinking quality."
### Standalone bidet fixtures
A standalone bidet is its own fixture next to the toilet, with its own water lines and drain. It's a bigger plumbing job. Phoenix's adopted plumbing code lists a minimum fixture supply pipe size of 3/8 inch for a bidet, and treats a bidet with a thermostatic mixing valve as needing a flow rate of 2 gallons per minute at 20 psi at the fixture. See whether you need a plumber to install a bidet for how that job differs from a seat.
What does each type need from your bathroom?
This is where the choice usually gets made. Here's a side-by-side look.
| Type | Water | Power | Where it connects |
|---|---|---|---|
| Non-electric attachment | Cold only | None | T-valve at the toilet fill valve |
| Dual-temperature attachment | Cold plus hot | None | Toilet fill valve plus the sink's hot supply |
| Electric seat | Cold only, heated by the seat | Grounded GFCI outlet | T-valve at the toilet, plug near the toilet |
| Standalone fixture | Hot and cold lines | None for the fixture itself | Its own supply lines and drain |
### Power for electric seats
Electric seats need a proper outlet, and the manufacturers are specific:
- TOTO's WASHLET guide says to always use a grounded (3-prong) outlet "connected to a ground fault circuit interrupter (30mA or less)."
- Kohler's guide for its tank-heated seat calls for a dedicated 120 VAC, 60 Hz circuit protected by a minimum 15 Amp GFCI, and says the outlet "should be located within 12″ (30.5 cm) of the toilet."
- Brondell's Swash guide says to only use a grounded GFCI outlet.
If there's no outlet within reach, plan for an electrician before the seat arrives. That's electrical work, not plumbing.
### Water pressure and temperature
Every seat has a pressure range, and it's worth checking against your home. Kohler's tank-heated seat calls for a cold water supply of 20 to 80 psi. TOTO's WASHLET guide lists a range of 7.25 psi dynamic to 108.78 psi static.
The City of Phoenix says an acceptable pressure range within the city is between 40 and 100 psi. That means some Phoenix homes can sit above the top of a seat's range. If you don't know your pressure, see what your home water pressure should be before you buy.
Temperature is a Phoenix detail too. TOTO says the water supply temperature should be within 32 to 95°F. Phoenix's 2025 water quality report lists water temperatures of 47 to 92°F. That's inside TOTO's range, but closer to the top than most people would guess.
Which type makes sense for my home?
Start with what's already there, then match the seat to it.
- No outlet near the toilet, and you want the simplest install: a non-electric attachment.
- No outlet, but you want warm water, and the sink is right next to the toilet: a dual-temperature attachment.
- An outlet within reach (or you're willing to add one), and you want a heated seat, warm water and a dryer: an electric seat.
- A remodel with room for a second fixture: a standalone bidet.
### Will it fit my toilet?
Check the bowl shape and the mounting holes before you order. Brondell's Swash guide shows separate elongated and round versions, with dimensions for each. Measure your bowl, and compare it to the product's drawing.
Also check the supply line from the wall to the toilet. Brondell's attachment instructions say that if that line is a rigid pipe, you will need to buy a flexible water supply hose to replace it before installing. An old or kinked line is worth replacing at the same time anyway.
### Does the toilet need a working shutoff?
Yes, and it's worth checking before you buy anything. Every type of seat in this guide connects at the toilet's water supply, so you'll need to close the valve behind the toilet to install it. Phoenix's adopted plumbing code already calls for a shutoff valve on the supply to each plumbing fixture in a home, with bathtubs and showers as the exception. If yours is stiff, won't close all the way or drips at the handle, fix that first. See why a shut-off valve leaks at the handle. A seat install is a good time to swap an old multi-turn stop for a new one.
### Can I use my own hoses and fittings?
Use the ones that came in the box. TOTO's guide says not to use water supply hoses and junction valves other than those supplied with the product. Kohler's guide for its electric seat says not to use an extension cord with the product.
Once you've picked one, our step-by-step guide to installing a bidet attachment walks through the hookup. If the toilet itself is the problem, see whether it's time to replace the toilet first.
HQ is licensed and insured and gives free estimates with upfront pricing. If you'd rather not handle the water connection, or you're adding a standalone bidet, we can plumb it for you.