We're digging footers for a guest house and came across this pipe. It's buried about 12" down, it's orange and about 1" diameter and has raised ridges running lengthwise (you can see them as black lines in the photo). The pipe had quite a bit of water in it that drained out, but nothing under pressure. We checked all the sprinkler systems zones (it's an older system) and it's not connected. I've never seen this kind of pipe before. It's an older property (main house is 150 years old) but this pipe is way away from the main house, near the property line, with no logical start or finish. Any ideas?
It looks to me like ribbed HDPE conduit used in directional boring. Orange is the color that is traditionally used for telecom applications. I'm guessing that this is either a fiber-optic back haul cable or an area trunk line, and the water that leaked out was due to a bad conduit seal somewhere. Assuming that your phone is still working, I'd call either the "call before you dig" locator service that didn't flag it or local telecom utilities to see if it belongs to any of them.
Finally we determined that it's a telecom conduit (with no wires but water inside) from a LONG time ago (although I'd like to know HOW long ago...). At least that's the general consensus, and there is a telephone pole lying in the general heading of the pipe, with an orange (albeit completely different) pipe coming up out of the ground. So we're capping that sucker, assuming some water got into it from a few decades ago, and hoping that some guy six blocks away doesn't turn on his water and wonder why nothing comes out, while a lovely Koi pond forms behind out guest house.