How do I install a bidet attachment?

A little checking up front saves a second trip to the store.

• A working toilet shutoff valve. Phoenix's adopted plumbing code requires a shutoff on the fixture supply to each plumbing fixture in a home, other than tubs and showers. Turn yours before you start. If it won't close or drips at the handle, fix that first. See why a shut-off valve leaks at the handle.
• A flexible supply line. Brondell's instructions say that if the line from the wall valve to the toilet is a rigid pipe, "you will need to purchase a flexible water supply hose to replace it." It lists the top connection as a 7/8-inch ballcock connection and the bottom as 3/8-inch or 1/2-inch female compression.
• Room under the tank. The T-valve mounts right under the tank, so you need to be able to reach the fill valve connection.
• For a warm-water model, a nearby sink. Dual-temperature attachments tap the hot water under the bathroom sink. More on that below.
• The parts in the box. TOTO's WASHLET guide says not to use water supply hoses and junction valves "other than those supplied with the product."

A towel and a small container under the tank will catch the water that's left in the line.

These steps follow Brondell's installation guide for a standard non-electric attachment. Other brands are similar, but read your own manual too.

### 1. Remove the toilet seat

Lift the hinge covers and remove the seat bolts with a screwdriver. Some seats loosen from underneath instead. Set the seat and hardware aside, because you'll reuse them.

### 2. Shut off the water and empty the tank

Turn the toilet's shutoff valve off. Then flush and hold the handle down to empty the tank. Brondell says to "Flush toilet and hold down handle to completely empty toilet tank." Kohler's guide adds a container under the fill valve "to catch any excess water."

Disconnect the supply line from the fill valve, which is the threaded connection on the bottom of the tank.

### 3. Install the T-valve at the fill valve

This is the step people most often get wrong. Brondell is explicit: the T-valve "should be installed at the Fill Valve under the toilet tank, and NOT at the cold water supply coming from the wall." Kohler says the same for its seat: "Connect the T-valve directly to the toilet fill valve."

1. 1Thread the T-valve onto the fill valve connection with the rubber washer that came with it. Brondell says to make sure the washer is properly seated, "tapered side up."
2. 2Connect the supply line from the wall to the bottom of the T-valve.
3. 3Connect the smaller end of the bidet hose to the open side of the T-valve.

Don't crank these connections. Kohler's guide warns against cross-threading or overtightening and says "Hand tighten plus one-quarter turn is sufficient for tightening."

### 4. Mount the attachment

Snap the mounting brackets into the attachment, line them up with the seat bolt holes on the bowl, and set the attachment in place. Brondell says to put the nozzles close to the back of the toilet, "leaving a slight gap between the toilet and the nozzles."

Put your seat back on top and bolt it down through the attachment. Brondell says to tighten it "so that the bidet attachment and seat do not move." Before turning the water on, set the control knob to off. Brondell's guide says to make sure it "isn't turned to one of the operating positions to prevent water from accidentally spraying out of the toilet bowl."

### 5. Connect the hose to the attachment

Connect the open end of the bidet hose to the fitting underneath the attachment.

### 6. Turn the water on and check for leaks

Open the shutoff valve slowly. Brondell says to check for leaks, then "Wait 5-10 minutes, check again." If a connection weeps, it says to check the rubber washers and make sure the connections are tight and secure. Run the bidet once, then check every connection again with a dry towel.

A dual-temperature attachment needs one extra connection: hot water. Brondell's SMB-25 manual says its hot water T-valve goes "at the hot water supply under your bathroom sink," and that this should be a 3/8-inch connection. If the connection there is 1/2 inch, the manual says you'll need a reducing adapter.

The hot side goes in like this, per the SMB-25 manual:

1. 1Turn the hot water valve under the sink all the way off.
2. 2Open the sink's hot tap until no more water comes out.
3. 3Disconnect the sink's hot supply line from the shutoff valve.
4. 4Install the hot water T-valve on the shutoff, and reconnect the sink's supply line to the top of the T-valve.
5. 5Connect the hot water tubing to the T-valve. The manual cautions not to over-tighten the pressure cap, because you risk damaging the tubing.

The rest of the install matches the cold-only steps above.

### What about an electric bidet seat?

An electric seat replaces your toilet seat instead of sitting under it, and it needs power. Kohler's guide for its tank-heated seat calls for a 120 V GFCI- or ELCB-protected receptacle located within 12 inches of the toilet, and says not to use an extension cord. The water hookup is the same T-valve at the fill valve. For a side-by-side look at the options, see the different types of bidet toilet seats.

Most problems trace back to a handful of slips:

• T-valve on the wall valve instead of the fill valve. Both Brondell and Kohler put it at the fill valve.
• Missing or upside-down washer. A leak at the T-valve often comes down to the washer. Recheck it before tightening harder.
• Overtightened plastic connections. Kohler's rule of hand tight plus one quarter turn is a good one to remember.
• Knob left on. Set it to off before you open the water.
• Rigid supply pipe. Replace it with a flexible line first, as Brondell's guide says.

Call a plumber if the toilet shutoff won't close or leaks, if the fill valve connection is corroded or cracked, if you want a standalone bidet instead of a seat, or if you'd rather not handle the connection at all. See whether you need a plumber to install a bidet. If the old supply stop needs to go, our guide to replacing a toilet shut-off valve covers it.

HQ is licensed and insured, and every estimate is free with upfront pricing. We can install the attachment for you, or fix the valve that's keeping you from doing it yourself.