I have an open trench and I might as well fill it with expensive plastic.

I went by the local irrigation supply to get 1 inch HDPE water line and was told gophers eat that around here (south-central WA) and I should stick with PVC. I want to avoid joints under the future patio.

I then realized I had ordered HDPE gas pipe for said trench. Will this get gnawed on by gophers too? I have a lot of gophers here although none of my surface PE irrigation lines have been damaged.

Is there any truth to this old wives tale or is it just rumors on the old-timey internet forums? Should I use copper gas lines to be safe? Local AHJ just shrugged at the question.

  • 1
    I am pretty sure the only one who can answer this well is Carl Spackler. Anyone else is just guessing.
    – DMoore
    Nov 15, 2020 at 6:28
  • "You wanna listen to the man, Pay attention to the magistrate, And while I got you in the mood, Listen to your, Own heart beatin'* (Dip, dip, dip, dip, dip, dip, dip, dip) (Boom, boom, boom, boom) I'm Alright, Nobody worry 'bout me" - youtube.com/watch?v=rbQgaHZOFZ0
    – Alaska Man
    Nov 15, 2020 at 19:04
  • I walked right into this joke. Thanks much! Time for a re-watch.
    – brik
    Nov 15, 2020 at 20:11

2 Answers 2


I feel your pain, I live in Western Washington and have the same issue. One way to protect against gopher damage is a larger pipe. Like 2" conduit or similar. They can't open their mouths enough to gnaw on it. But it's not an "old wives tale". Gophers can do a lot of damage to buried lines. So if I were doing this, I'd at least put in 2" conduit (or pipe) in areas that would be difficult to access later. If you want to go further, put it all in conduit. Depending upon how long the run is, it's not really all that expensive and good insurance.

  • Would Schedule 80 PVC be suitable and affordable for a conduit for either a gas line or a water supply line in HDPE? A plumber here in Dallas uses Sch 80 PVC for the sweep 90s as conduit for PEX. Of course, the diameter of uch conduit would be important. Nov 15, 2020 at 18:07
  • Thanks for confirming it’s a real concern. Given the number of lines and distances involved I don’t want to mess with the outer conduit. I think I’ll redesign the system to use copper and take all these yellow coils back to the orange box.
    – brik
    Nov 15, 2020 at 20:10

Here in Phoenix, AZ the gophers are a problem. Any buried thin wall black poly has a short life span. 4 year old 3/4" poly on the surface is doing fine so far, but sun exposure will be a limit for this. Plain old buried sch.40 PVC seems to hold up just fine. My incoming 1" PVC water line is 15+ years old. The various 7 year old 3/4" PVC SCH40 irrigation lines with a 12" bury are all doing fine so far. Not sure if PVC gas line would be an option. 20 years ago it had a problem with getting brittle from the odorizing agent. Don' know if this has been fixed.

  • HDPE water/gas pipe is universally thickwall stuff similar to PEX piping -- not the thin corrugated PE used for conduit and drainage service Dec 18, 2021 at 2:38

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