We're currently building and have had a transition of PMs. They're chasing down confirmation that they ran an R/O line from the sink to the fridge. I want them to get this sorted because cabinets are delivered next week and I do NOT want them cutting thru them later b/c they screwed up. Can you tell from this (fridge space) if this is an R/O line? TIA

Impossible to tell from this picture. Your plumber will know. Or you can get in the attic and trace the water line.

Not an R.O. filter

Might be a water hammer arrestor in wall recessed box
ala like these are
https://accortechnology.com/product/washing-machine-box/wholesale/4allbox

R.O. example Culligan/others

I understand the system will go under the sink. But there's supposed to be a line that runs from the system to the fridge to supply the water there. I'm just frustrated that they aren't able to confirm it's done.

If cabinets aren't in yet, it should be extra easy to find at the sink end? Doesn't sound like it was installed.

Hard to tell without more information. If your PM is asking if that's an RO line, that's an eyebrow raiser.

Good point. I'm going to pin him down hard in this Monday.

This will all be worth it. This will all be worth it.

That's definitely a water stub out with a 1/4" fridge connection, but you can't tell what is supplying it from just a picture. Is the RO already installed under the sink? There should be an identical valve under the sink that will eventually be connected to the water supply (either the RO or city cold water).

No, R/O isn't installed yet. We don't have cabinets yet.

Is there an identical 1/4" valve under the sink where the RO will be installed?

Typically under-sink you'll have a hot and cold sink supply and a hot supply for the dishwasher (assuming the dishwasher will be over by where the sink is). If there's an extra valve with 1/4" connections, that's probably the supply side for the RO to the fridge and there shouldn't be any pressure to it as it's just an empty pipe at the moment.

https://accortechnology.com/4all-box-ice-maker-with-flowtite-4all-valve-polymer-arrester-and-high-performance-connector
I think that box supports putting a drain in if you want failure to drain somewhere besides into your wall but likely does not work well when you install upside down

I laughed, but its oriented correctly for the water line above. Ice maker connection (sealed box to prevent in wall leaks). Nice, gonna add to my specs.

I don't think so
https://accortechnology.com/images/pdfs/619_4ALLSpec_IMB_2.pdf
it has the provision at least to have a 2" drain line and that is on the top, so unless we get congress to change the laws of physics and allow water to flow up hill its wrong. In this case it does not look like they intend to plumb the drain option.

Do you still think it is a drain line?

If you look at the picture it has a 2" drain line in the bottom of the box which is on top in this orientation. The offer boxes without drainage but this one is designed to be plumbed to a drain line.
Its not the seal that prevents in wall leaks it the fact that any leaks leave vis the drain not into the wall. I have one similar on my washing machine hose well.

OP back. Came out to the house. Here's a pic of kitchen sink area

Found a better pic. Maybe it's the black line headed to the right?

I stand corrected. Good to know.

Yeah, looks like that blue pex line on the lower right is your open run for the undersink RO to the fridge. I see a hot and cold supply for the sink and a hot for the dishwasher there too.

SCORE! Thanks!