Copper stubouts for Pex or not?

[rsaritzky]

This topic is duscussed every few years here, but I wanted to get some 2025 opinions. I'm starting a remodel on a 100-year-old house in Pasadena, CA. I'm going to do a full repipe. Most plumbing contractors are going to recommend Pex for cost purposes, but I'm concerned about the "strength" of the stubouts. I've done my own minor plumbing repairs for many years, and when an angle stop fails, it takes a bit of "pressure" to remove the old stop. But I can always sand the existing copper stubout and put a wrench on it to attach the new stop.

Pictures of even the most "robust" Pex stubouts concern me they seem "flimsy".. There are "sharkbite" style connectors and compression fittings, neither that give me a lot of confidence.

Pasadena's water is not acidic, and I haven't checked for Chloromines yet. But assuming not, I'm assuming that pinholes in copper stubouts is not something to be concerned about.

What does anyone think?

 

[James Henry]

Yes. Use copper stub outs with 1/4 turn compression stops. If they ever fail you just loosen the nut that holds them on and install a new one.

 

[Sponsor]

 

[JohnCT]

I like PEX, but hate PEX stubouts. Looks cheap and less serviceable IMO. I would use copper stubouts as long as the water quality won't abnormally affect copper.

John

 

[John Gayewski]

Copper stub outs with pex unless your water is acidic.

 

[LLigetfa]

When installing the angle stops, leave them long enough to slide the compression nut back far enough to get an olive remover on it to split the old ring.

 

[Eman85]

I'm not a plumber, but I agree with using copper stub outs. In my shop building my PEX is surface mounted and the valve is just connected to the PEX stub out. Doesn't look pretty but it's functional and all of it is easily replaced/repaired if a problem. In my home when I plumbed it I used copper stub outs securely mounted in the wall so valves would be easier to replace or service if needed, and they look good.

 

[Reach4]

What I did for a retrofit where I fished the new piping thru the plaster wall:

Attaching PEX pipe inside a finished wall

I am selling this home and the home inspector complains that the stub outs under the bathroom sinks are not strapped inside the wall. The house is plumed with PEX or some equivalent. It has been that way for 12 years since new with no noises or problems, but the buyer wants it secured. Is there...

terrylove.com

I suggest somebody productize a PEX / Aquapex input stop valve, with a plate that screws to the wall. Better still, that plate could be covered with a standard or included split universal escutcheon. https://www.lowes.com/pd/Keeney-0-5-in-Chrome-Universal-Escutcheon/3131285

Or how about something like this, except there would also be a screw-plate that accepts screws into a wall and takes the forces:

Finishing Valves 611-PRPX3LE-31

dahl product #611-PRPX3LE-31 is suitable for Plumbing, Faucet, Toilet, Pedestal Sink and Bidet applications.

dahlvalve.com

So while the wall is open, the copper stub-outs would be ideal. But a nicer retrofit solution would be good for retrofit cases.

 

[Integrity Repipe]

Your concerns are valid—PEX stubouts don’t have the same rigid feel as copper, which can make them seem less durable, especially when replacing angle stops. However, properly installed brass PEX stubouts or PEX-to-copper stubouts can provide the best of both worlds. Many plumbers use a copper stubout with a PEX adapter, securing the fixture connection while keeping the flexibility and cost benefits of a PEX system. Given that Pasadena’s water isn’t acidic, pinhole leaks in copper may not be a major issue, but chloramine levels can still be a factor, so it's worth checking. If longevity and ease of future repairs are your main concerns, a hybrid approach using copper stubouts with PEX supply lines is a solid choice.