Is it acceptable to use PVC pipe (like schedule 40) under the house to plumb from the main water supply to hose bibs that punch through to the exterior? I have an unfinished cellar space, and I'm in California in a climate that gets a few freezing days in the winter.

The reason for this is that I want to have essentially 3 sets of (cold) water distribution lines under the house:

  1. Filtered water for drinking, going to the kitchen and bathroom faucets.
  2. Unfiltered water for all other interior use.
  3. Irrigation water for exterior uses, that I can shut off and drain for winterization.

For this last set, I'd want a single shutoff and drainage point, but I don't want to run a separate set of fat and expensive copper lines to each hose bib around the house. Everything inside the house and in the cellar does not need to be drained or winterized, only pipes that penetrate to the outside.

  • 3
    first of all, start with PEX. Copper is dead
    – Tiger Guy
    Oct 3, 2022 at 6:51
  • Why is copper dead? I don't want to use plastics if I can avoid it.
    – Victor Liu
    Oct 4, 2022 at 16:57
  • costs so much and doesn't last as long
    – Tiger Guy
    Oct 4, 2022 at 19:05

1 Answer 1


Why not use frost free bibs so you don't have to winterize? They're pretty much the standard now.

If you must use regular bibs, I'd use pex as it tolerates freezing more, is more versatile, and still relatively inexpensive. While you can use PVC for drain, vent, etc, it's not approved for [hot] water distribution.

Lastly, and most importantly, I'd avoid separating out distribution in the home. Better to centralize your supply and avoid "filtered" and "unfiltered" water inside the home. Someone will come along down the road and borrow a branch from the unfiltered line and hook it up to a fridge, sink, etc. Keep it simple: cold potable water and hot potable water. Leave "unfiltered" irrigation style distribution to outside the home only (city watering systems, etc)

  • The reason PVC isn't considered approved for water distribution is because it isn't usable for hot water -- CPVC is required instead Oct 3, 2022 at 11:47
  • 1
    PVC that is marked for potable water use is certainly available, and common, and widely used for cold water distribution. I'd still choose PEX (or non-crosslinked polyethylene well-water tubing for cold.) But it's false to claim that PVC is not approved for water distribution. PVC-DWV is not, but that's not the only PVC pipe available.
    – Ecnerwal
    Oct 3, 2022 at 13:29
  • Appreciate the clarification, I should have noted that. I'd still argue PVC is a poor choice inside a home compared to current products. Answer edited.
    – Justin C
    Oct 3, 2022 at 19:41

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