trenching with finesse

Knowing where the source is, the control valves, the heads, you can guess where they are likely to be. You could also take a somewhat longer route that may increase the chances of missing them. But in the end, you do what you gotta do and fix the ones that you hit.

What's wrong with contacting JULIE? They are free.

do they mark, or find, user installed drip or spray water lines? i thought they just did utility installed lines.

That's my thought too. If the irrigation pipe is metal, a metal detector should work to map them out. I don't know if he's talking lawn sprinklers or what. For that I would expect a grid pattern from sprinkler head to sprinkler head, but I'm just guessing.

Non metallic stuff like irrigation lines will be quite difficult to locate. The only way I can think of is to rent a locator transmitter and receiver set from United Rentals or whoever, and in order to make it work, get a steel fish tape, disconnect the irrigation lines at the valve bank and push the fish tape down them with the transmitter clamped around the fish tape at the valve location. Considering the relative ease and low cost of repairing a severed irrigation line I'd be inclined to just chew through them and be done with it.

My father would swear that divining rods work.

Your father should find someone who can do it and then collect his half of the one million dollar prize.

If the irrigation lines are the typical vibratory plow installed poly pipe, there is no metal for the locators to work on. Those locators use a clamp on inductive signal transmitter to inject a signal into wires, metal conduit, etc. for the locator to pickup. See my other post for the idea of pushing a steel fish tape through the irrigation pipe from the valve bank end to provide a locatable piece of metal in the tubing.

dig hole at either end of desired route and use a drill with lots of extentions to drill a path for the new whatever ,..... its amazingly easy and fast

Fascinating reading. Thanks. From a claim by a Yo-yo dowser:

There are an awful lot of loons out there. I suppose that's what a million dollar prize does: flush them from cover.

-- Bobby G.

Interesting. The irrigation pipes I see most are continuous flexible poly pipe installed with a vibratory plow and thus have very few obstructions.

Fix them later, unless your time isn't worth much. Don't bother calling someone to attempt locate them, you'll pay more than it's worth. Universal unions can be had for about 4 bucks a piece.

That's what I ended up doing. It was cheaper to fix the irrigation system than to delay the propane company. They chewed through two lines (running together) and hit a head. They offered to have it fixed. It only cost me something like $20 and an hour to fix the whole thing so I didn't bother sending them the bill.

Spare the rod...

Thanks to all for feedback and suggestions. I'll call before I dig, but other than using some logic about where the sprinkler pipes might be, I'll just assume that I'll end up breaking a couple of them. Didn't know that non-metallic pipes could be located, so that's good info for another project, but probably not worth the trouble for this one.

If you are that worried about damaging them and having to repair them, you could dig them up by starting near a sprinkler head close to where you want to trench and see which direction the irrigation lines are running in...

that's funny! I worked for a lawn and landscape company and that (divining) is how we always located them.. Too bad you're too stubborn to try it.

For 20 dollars you can get a device that adds Plutoinium 238 to your irrigatiion water. Then mount a geiger counter on the ditch witch and you're good to go.

Wait, I googled and the Plutonium costs $500. Forget it .

I was thinking of steel wire and a metal detector.

Greg