Silly question regarding toilet water supply line -- what size?

[Clyde15]

I might need to replace the supply line that goes from my shut off valve to my toilet tank. It's an old connection -- a metal pipe (as opposed to a braided flex hose)
Here is my question -- the nut on the supply line that connects to the shut off takes a 5/8 wrench. If I wanted to buy a braided flex hose - without replacing the current shut off valve--- what size would I buy? I am seeing flex hoses that are 3/8, which would be too small for my shut off. And I see 1/2. But I don't see any 5/8 flex hoses. I would think that if the wrench size on the nut is 5/8, that is what I would be looking for when it comes to these hoses -- but perhaps I am wrong -- and it is the 1/2 that I would buy?

 

[hj]

5/8 would be too small for a 1/2" nut16. Maybe 5/16" copper.

 

[Sponsor]

 

[hj]

5/8" is somewhat small for 1/2", but may be 5/16" copper compression, which is rare but available in a flexible hose. You just have to be more diligent to find one.

 

[Bacon]

Most supply lines and shutoff valves are 3/8" compression. This refers to the pipe size, not the wrench size of the nut. There are other sizes, but those are not common on fixtures like toilets. However, you said it's old so who knows.

 

[Clyde15]

Thank you for the quick responses. I am going to disconnect the existing supply line and compare with what they have in the store. I'll post a follow-up in case someone has similar situation.

 

[Terry]

Stops come in
3/8" Comp
7/16" Comp
1/2" Comp
1/2" FIP

 

[Clyde15]

Confirmed. It is 3/8 comp with a nut that uses 5/8 wrench.

 

[JRC3]

Confirmed. It is 3/8 comp with a nut that uses 5/8 wrench.

I keep 2 wrenches in my bag...7/16 and 5/8. The 5/8 for this reason only.

 

[Plumber69]

I went to do plumbing at a guys house. He started and wanted me to finish. I get there and he ran 1 inch copper off half inch back to half inch stubout

 

[CountryBumkin]

Maybe he was just "using up" the pipe he had laying around.