Need help tapping into supply line; threads don't match

I am tapping into my toilet's water supply line to provide water to a bidet toilet-seat.

The 1/2 in. fittings supplied with the bidet would work on the fittings inside my toilet... but I can't reach them. The toilet is installed too close to the wall.

But the valve at the wall is accessible. There is a metal braided line connecting the toilet to the valve assembly coming out of the wall.

Here's what I'm *trying* to do... though I'm open to a better solution:


I turned off the valve, unscrewed the braided toilet supply line, and measured the fitting with a template... I thought it was a 1/4" line, so I bought tee depicted above, and... the 1/4 in. (female) part of the tee wouldn't screw onto the wall supply valve's fitting. Ugh...

The braided hose from the toilet could (almost/barely) fit onto the 1/4 in. (male) part of the tee... but I think I've just got the wrong tee... is the wall supply fitting not NPT? If not... what is it?

See pics... might help explain.


Anyway, can someone provide some advice? Is there an easier/better way to do this?

I can't see your pictures, and I am not an expert.

I have rental properties and do most of the plumbing work myself. Every shutoff I have ever seen for a toilet has 3/8 inch male threads.

jeffmattero76 said:

I can't see your pictures, and I am not an expert.

I have rental properties and do most of the plumbing work myself. Every shutoff I have ever seen for a toilet has 3/8 inch male threads.

Click to expand...

3/8 inch NPT?

Pics seem too close to know what is going on.

There are at least three or four common thread sizes of shut off valves for a toilet supply line.
And some old sizes that you still might run into.

Several iron pipe sizes, and several compression sizes.

Jeff Handy said:

Pics seem too close to know what is going on.

There are at least three or four common thread sizes of shut off valves for a toilet supply line.
And some old sizes that you still might run into.

Several iron pipe sizes, and several compression sizes.

Click to expand...

Not sure how seeing the bigger picture would help, but it's moot; not enough room to maneuver for better pics.

What are the "three or four common thread sizes"?

The place was built in 2016, if that helps...

If you are in USA, the threaded output of the shutoff valve is pbly 3/8 compression threaded.

On your second pic, I see F1950 1/2”

Just curious, but we get this question at least once a week
People trying to make their own sprayers/bidets. I just don't get trying to fabricate something that is readily available as a complete kit.

The threaded outlet of the supply valve at the wall looks like 3/8” compression thread to me. And so does the female end I can see, of your flex supply line.
Hope that is the info you needed.

The threads on your bright brass fitting look slightly farther apart, or coarser.
And the brass threaded end looks slightly narrower in diameter than the chrome threads it is butted up against.

I think he has a ready-made toilet seat bidet kit, just can’t figure out how to get water into it.

Where are the instructions for the "sprayer/bidet? If everything else fails.. Read the instructions.
That said... Every bidet seat/sprayer I have ever installed has the mixer valve mounted to the fill valve/ballcock and the supply line mounts to the mixer and appliance.
If you don't have the instructions look online for the brand/model #.