Any way to locate plastic underground water lines?

[phylodog]

I've got a crew coming in the morning to start an addition onto our barn. There is a water line running out to the barn now which I capped below ground a few years ago when the hydrant began leaking. We don't need water there so it was cheaper/easier than buying a new hydrant and I can dig it up down the road if needed. They're be digging post holes first thing and I have the tools and materials needed to plug the line if they hit them. I'll be putting the backhoe on the tractor as well so if it happens it shouldn't slow things down too much.

I've been operating under the assumption that there is no way to locate the plastic lines underground but figured it was worth asking. We had (have) 3 hydrants in or near the barn but I'm hoping only one of them is in danger of being hit, that being the capped line. Other than standing by ready to get in there if it happens, anything else I could do aside from dousing rods?

 

[edwea]

Dousing rods are pretty effective. If there isn't a locate line with the water line, start dowsing!

 

[Crandall Crank]

What's wrong with dousing rods? I use two copper rods and "witch" with them. I know some people don't believe in this, but it works for me and my daughter.

 

[snapping turtle]

Drain the water. Send fishtape down waterline. Now get out the metal detector and you have your plastic water line found.

 

[phylodog]

I'm not claiming dousing rods don't work. I am skeptical but may give it a shot.

 

[Crandall Crank]

Try "witching" over a known water line. You'll see how the rods turn...if you were closer, I'd come over and mark them for you.

 

[Mij]

We had to lay a metal tape along the underground pipes, like an old style vcr tape but metal, it was mandatory on construction jobs. But if you did the job yourself you probably didn’t do that. But if done by a company they may have. Just a thought.

 

[red_zr24x4]

We install plastic mains and services with a copper wire to locate them.
Cut a metal coat hanger about 16" and bend it in a L . I've witched gas, water, electric...anything with a "flow" . The rod will spin

 

[DoggyDaddy]

Dang... bunch of witches around here!

 

[phylodog]

We had to lay a metal tape along the underground pipes, like an old style vcr tape but metal, it was mandatory on construction jobs. But if you did the job yourself you probably didn’t do that. But if done by a company they may have. Just a thought.

I'll check but I didn't notice anything and I've been down to the base of all three hydrants. Doesn't mean I didn't notice it in a dirty hole though and I have no idea how long the lines have been in the ground.

 

[Bugzilla]

Dig a random hole. Good odds you will hit the line!

 

[phylodog]

We install plastic mains and services with a copper wire to locate them.
Cut a metal coat hanger about 16" and bend it in a L . I've witched gas, water, electric...anything with a "flow" . The rod will spin

Does that mean there must be fluid moving through the line? The one I'm worried about hitting is capped so no flow through that one.

Not that it really matters I guess. The holes gotta go where they gotta go and if I have to cap a line and do something with it later I will. Just curious more than anything I guess.

 

[Creedmoor]

Drain the water. Send fishtape down waterline. Now get out the metal detector and you have your plastic water line found.

With the years installing irrigation, thats about the only way to reliably track out a line with no tracing wire.
You also can use a electric dog fence box to hook up to the metal fish tape, you can use an AM radio to track it out.

 

[Hkindiana]

When I bury a plastic water line, I drop a real copper Penny about every foot along the line - it is cheaper than copper wire, and gives a stronger signal to the metal detector

 

[gpasp101]

Every time I’ve found one it was with an excavator

 

[red_zr24x4]

Does that mean there must be fluid moving through the line? The one I'm worried about hitting is capped so no flow through that one.

Not that it really matters I guess. The holes gotta go where they gotta go and if I have to cap a line and do something with it later I will. Just curious more than anything I guess.

No, should be able to witch the line.
We've witched conduit also

 

[Mij]

Every time I’ve found one it was with an excavator

Almost an absolute surety.

 

[Creedmoor]

Almost an absolute surety.

I used to tease my bil, man when you dig in the dirt, your gonna cut utility's.

 

[phylodog]

I used to tease my bil, man when you dig in the dirt, your gonna cut utility's.

Nothing in this spot but the water lines. I've had the underground utility guys out to mark a couple of times and there is nothing on my property other than what's buried along the road. Once I'm 20' off the roadway I'm wide open other than these water lines and the septic.

 

[Mij]

I used to tease my bil, man when you dig in the dirt, your gonna cut utility's.

Yup. Another good way is drive a crane across a parking lot, or roadway.