Plastic water line locating is no easy feat. Plastic water lines are non-conductive and about as electrically interesting as dirt. These plastic-based pipes have evaded the grasp of many noble locators throughout the years.
This is a problem because, since the eighties, most new water pipes have been made of non-metal, non-conductive plastic. So how exactly do you find water lines underground? Read on for all the details.
Buried water utilities are broken into two categories: potable (a.k.a. drinkable) lines and irrigation (a.k.a. reclaimed water, non-drinkable) lines.
These water lines can be made from the following materials:
Generally, locating water lines involves GPR. This technique is largely ineffective for locating plastic water lines (or AC lines), though – for two main reasons:
Ground-penetrating radar (GPR) simply isn’t designed to locate deep, small-diameter, plastic or non-conductive lines of any kind.
If you’re a studious locator, you might say, “Well, if I can’t use GPR, what about a pipe locating wand?” While there’s merit to your thinking, a pipe locating wand will only work if there is a tracer wire buried with the line – which is basically never. (But bless those few contractors out there who actually do take the time to bury one!)
So, what’s the secret to plastic water line locating? Drumroll, please… it’s acoustic locating.
When other non-destructive testing (NDT) tools fail, acoustic locating emerges as the true hero. We’re big fans of acoustic locating because it can work on any pipe, regardless of the material.
The acoustic locators that we use at Enhanced Scanning send an acoustic wave through the waterline. This increases the line’s pressure by approximately two psi, with a pulse wave generator (PWG) attached to a pressurized hose bib, hydrant, faucet, or other water sources on the line.
Then, we use a digital processing unit, noise-canceling headphones, and a geophone to listen for the sound of the pulsing water underground.
No bones about it. Acoustic locating is a tedious process. But using a pulse wave generator (PWG) for this process has proven very effective at finding those otherwise unfindable plastic and asbestos cement pipes.
Many utility locate companies only try to use GPR to locate plastic water lines, which sometimes works. At best, this is extremely difficult. At worst, it’s impossible. It’s kind of like playing whack-a-mole and just whacking on all the holes because you know a mole might come through one. It’s inconsistent and unreliable. If you want reliable plastic water line locating, drop us a line at email@example.com.