Use permeable PEX for potable water (DWH)

[DrBoom]

I'm thinking about adding a heat pump water heater in a difficult to plumb location. We happen to have PEX to/from there for an old hot tub heat transfer system that heated the hot tub from the house boiler. We're never going to use that run for it's intended purpose (hot tub is conventional and elsewhere). Does anyone know if the PEX could be flushed and used for the DWH? I've attached a picture but it appears to say 3/4" CTS-WATTS radiant PEX with DIN 4726 oxygen permeability SDR-9 100psi@180F [NSF-pw ASTM F876/877].

Thanks, Jon

 

[Jadnashua]

PEX with an oxygen barrier costs more, but can be used for potable water.

 

[Sponsor]

 

[Breplum]

Typically it is not "approved" and doesn't have the cleaning and specific testing...should work fine. Don't drink the hot water at worst.

 

[DrBoom]

Thank you. The existing pipe runs I'm trying to re-use say NSF-pw on them which I think means they are safe for potable water but I'm looking for better verification that I'm correctly understanding the combination of markings and standards. As this run would become part of the potable water system, knowing that it is safe is important. I don't think just not drinking the hot water (while a good normal course of action) is sufficient given that cross contamination will occur even if backflow preventers are added.