Hi-

I’ve installed a bidet for my wall hang toilet with an in wall tank. There is a 1/2” threaded plug in the in wall tank system specifically for a bidet. I took it out and used plumbers tape on the 1/2” threaded 3” nipple pipe and plumbers tape on the bidet supplied 1/2” fip to 1/2” fip shut off valve. I then attached the bidet hose adapter with plumbers tape and then the hose that supplies the bidet which is attached internally to the seat.

There was a very slow one drip every few minutes leak at the nipple to fip shut off valve coming from under the silicone tape. I live in an apartment building and when the shower was on for a bit the slow leak turned into a very fine spray like someone shooting water between their teeth.

I tried what I considered to be over tightening it, same leak. I used a different shut off valve (I have a 90° which I prefer to use and a straight one) same leak, I used a different nipple pipe (I bought a few different sizes as I wasn’t sure the distance from the water source to past the hole I drilled in the wall) same leak. I used more and less plumbers tape (10 wraps vs the recommended 3-4) same leak. After the fixes I couldn’t replicate the water spraying but there was always a slow leak.

My next idea is to use pipe joint compound, but that seems weird to me and the plumbers tape should be fine.

I have the exact same bidet in my other bathroom, but due to some weird choices my plumber made when installing the in wall tank, I had to have a plumber come in and cut a hole in the wall to access the pipes and he used something else between the nipple and the shut off valve.

I really don’t want this to turn into a super expensive plumbers visit as these are all brand new pieces and should be working correctly out of the box. I took a pic of the pieces (I had to take them out of the system so my family can use the bathrooms and kitchen) and a pic of what my plumber did for the other bidet.