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Thread: How to Find Underground Water Leak

  1. #1
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    How to Find Underground Water Leak

    I find myself in a spot of bother and thought I'd run it up the flagpole by the braintrust here and see if anyone has any bright ideas.

    Problem: I need to find what appears to be a small, high pressure leak in a water line that runs across a field for 1500 - 1800' (somewhere around there), 4' deep at least, between the well house and my (and the parents') houses. Leak is small and there are no visible wet spots, which makes it a pain to locate.

    It would take me paragraphs to 'splain why things are set up the way they are, but the pump is on its own separate electric service and thus it's power usage can be known exactly easily. Well, this weekend night my mother informs me that the usage has been steadily increasing over the last few months. Normally it averages a mere 1 kW-hr/day, but over the last has been steadily increasing. I watched it over Sunday, and it was up to 4 kW-hr/day.

    The reason she hadn't informed me earlier was because she didn't want me to worry with any "hard work" until my hip was healed. My father is just getting too old to do much any more.

    So today I get on it (task number 4,359 in all the little things that needed attention around this joint that I hadn't felt like -- or cared! -- messing with). Because of the head drop (it runs uphill) I run the pump on a 60 - 35 psi cycle (to all you folks on city water that would seem like a trickle and you couldn't stand it )

    Well, after shutting off both houses, it was still leaking down. It would hit 60psi, then quickly bleed off down to around 40 -45 psi, then slowly leak on down to cut-on. It was cycling every 5 minutes (5 minutes, 4 secs to be exact). SO there's a leak somewhere, and one that leaks pretty fast above 45psi, but slows down below that. That explains why there's no detectable wet spots. I think.

    I check the pressure charge in the tank, and sure enough it was low, and I get back up. That helped a lot -- I should've checked that long before (one needs to do that about once per year). Anyway that increased the capacity in the cycle range. It still drops from 60psi down to 45 fairly quickly, but takes much longer to leak on down to cut-on due to the proper capacity.

    I'm watching it now, but it looks like that alone increased the cycle time by a factor of 4 or so.

    So I've got a small, high pressure leak to find along 1500' of water line buried at least 4' deep. I suspect over the 30 years it's been there, a rock has worked its way up against it and has worn a little hole in it. That, or a joint is failing.

    It seems the pros use sound to detect leaks, but here I may not have much luck. A cheap way to do that is get a stethoscope and use a piece of
    2" PVC pipe capped off with a piece of styrofoam cup as a resonating chamber. Walk the line and listen for a muffled hiss with the stethoscope.

    So that's what I'm gonna do when I get around to it. If anyone has any fancy leak detection methods that work better and faster, I'd appreciate it.

    To make it louder, one can increase the pressure by blocking of the line if possible and using air to get the pressure way up. I can do that if necessary, although with my luck, I'd probably blow out the seals on the
    cut-off valves.

  2. #2
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    Ater 30 years, my guess is a joint failure, because metal ones do rot with time. On my farm, this was always the cause (I'm assuming alkathene rubber pipe here). Once, I guessed correctly by measuring the 100 yard distance from the start to where there had to be a join if the pipe were laid using a full 100 yard reel of pipe. Could you use a metal detector to find a join, or is it too deep?

  3. #3
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    Dowsing?

    Acoustic detection might work (perhaps depending on soil conditions, etc). There are high-tech versions or this: http://takadu.files.wordpress.com/20...-detection.jpg

  4. #4
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    I don't know much about the subject, but I thought that a moisture detector might be worth a shot (with some probes to stick in the ground, and tie it to a multimeter). Even if the surface isn't obviously wet, the area near the leak may be wetter. However, when googling to see if anyone uses that idea, I saw a couple people mentioning trying it, but it appears that acoustic detection is the overwhelming favorite technique. I did find this article, which has some specifics about acoustic detection that might be useful:

    http://www.subsurfaceleak.com/find_leaks.html

    It talks about what kinds of sounds you would likely here, and the effects of different soil, depth and water pipe type. It seems that higher water pressure is important for sound intensity, so if possible, getting the pressure up would likely be useful.

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  5. #5
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    I don't know about underground water links but I had to comment on this:

    Quote Originally Posted by publius View Post
    ...run it up the flagpole by the braintrust here and see if anyone has any bright ideas.
    I think that may be one of the biggest mixed metaphors I've ever come across in the wild!

  6. #6
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    Too bad you can't time the pressure change moving in the pipe. If you had a certain max pressure at each end and it drops to 45 psi at each end at different times, you could ball park the distance from each end to the leak. Exactly how you would do that is beyond me.
    Solfe

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  7. #7
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    My first guess would be the tee between the two houses, if you can guess where that is. If you use stethoscope there is a mechanical type with a rod you can stick in the ground.
    Second suggestion is a bit drastic.
    First you check the flow rate carefully.
    Then close off the taps and apply suction to the supply pipe for one minute.
    Then repressurise and open one tap and time the appearance of the brown water sucked into the leak.
    You should be able to estimate the distance back from the tap.
    Then use the stethescope.

  8. #8
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    May I assume you've checked all the above-ground portions of the line? And all of the using fixtures in the houses? Oops -- re-reading, I see you've shut off both houses and still had the loss. I was about to suggest that!

    One thought that occurs to me is to temporarily replace the underground line with something on the surface -- a bunch of garden hoses, for example -- and make sure the problem goes away in that case.

    It may be cheaper to just run a new line than spend the amount of time needed to isolate the leak.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  9. #9
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    Quote Originally Posted by Van Rijn View Post
    I don't know much about the subject, but I thought that a moisture detector might be worth a shot (with some probes to stick in the ground, and tie it to a multimeter).
    I had the same thought about it being wetter deeper down near the leak. That made me think of crossing one of these with one of these.

  10. #10
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    They used to use Freon and Freon detectors to find leaks like those. Frowned on now of course.
    However I think my suction idea above at post 7 might work. Of course there are many ways to get some suction.

  11. #11
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    Success! Found it and fixed it, but boy it was a doozy. I haven't worked that hard in a long time and I'm going to take a shower and collapse. I'll tell the details later, but the root cause was indeed a root from a little cedar tree. The leak was close to well house itself and not in the field. I don't know why it didn't wet the top of the ground, but about 1 foot under the leak zone, it was a quagmire. Got the tractor with the loader stuck and all that good stuff and by the time I was through, I was covered in mud like some mud wrestler. Wasn't anything to do but get down in the mud and cut the pipe and glue in a replacement.

  12. #12
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    I was about to suggest emptying the pipe of water, then pressurizing it with air with a mercaptan added, then just follow your nose.
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  13. #13
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    Well, that certainly fixed things. Power usage is now back to normal. The meter hadn't clocked even 1 more kW-hr in 24 hr since I fixed the leak. I suspect now that I've got the pressure tank charge where it's supposed to be, it will be a little less than 1 kW-hr per day average. Again, one should check that about once per year. Those air molecules under pressure will find a way out over the long haul.

    Now, the adventure of finding that stupid leak. I went up to the auto parts store and got an el-cheapo mechanic's stethoscope. If you aren't familiar, it's a stethoscope with a little metal rod "probe" which is ideal for probing for bearing and valve sounds. I was going to see what that would do with a metal rod driven in the ground. If necessary, I was going to get a (more expensive) doctor's stethoscope from the drug store (those things can run up into several hundred dollars, but fortunately the drug stores have cheaper ones that run in the $20 - $50 range) which might have been better for a pipe resonating chamber pushed in the ground.

    So I get the stethoscope and go down there, expecting for an all-afternoon little job of trekking up that field listening and probably no luck. But, first thing I do (after discovering the thing will nearly blow your eardrums out with a pop if you let the probe hit something
    hard...) is put the probe on the faucet body right outside the well house.

    Lo and behold, there I hear the crystal clear, loud and clear, unmistakable sound of water leaking. It was the tell-tale hiss with a little gurgle riding on top. I figured it had to be close to transmit the sound that well. It was PVC pipe, mind you, not metal. Heck, maybe a water column can carry the sound well, but I don't know.

    So I take my metal rod and hammer and start probing along the line path. Now mind you the ground around that well house wasn't soaked or even unduly wet anywhere. About 20 - 30' from the well house, right before the boundary to the field, I drive the rod down in a spot. It goes down about one foot, and then resistance to driving collapses. It's mush underneath, about 12" - 16". Thar she blows. I put my stethoscope on the metal rod to see if I hear the sound, but it was quiet, which shows that would've been futile anyway. That mush was muffling the sound and only the water pipe itself was carrying it.

    You'd just have to see it to picture the lay of the land. The well house is at my grandmother's old house place, the house of which burned down in the mid-90's. They drilled that well for her back in the late 70s or so, when the old well she was using gave up the ghost. It was such a good well, capacity wise, that it was more than capable of supplying several houses, and that's what gave my father the bright idea of hooking up to it, running the line across the field. Our own well up here at the time was an old bored well with a jet pump/foot valve setup. Those things are notoriously problematic, and just to make you mad, will malfunction at the worst possible time -- freezing cold, pouring down rain, or so hot with the sun bearing down you can't stand it -- and on a weekend when the hardware stores are closed for any supplies you might need to fix it. Anyway, the new (at the time) one used a submersible pump and those things will last forever with no problems. Only problems are up top.

    I was just a kid then, and then later, I hooked my own self to it rather than drill my own of course. Well drilling is hit and miss around this area. A neighbor went 600' a few years ago (well, the well drilling outfit went 600' without him knowing it, hoping to get enough capacity and then charge him full footage -- they charge per foot, with a reduced rate (half or even 40%) for a dry hole, but charge the full price if they hit good water). There was water there, but no capacity. They then moved a few hundred feet over (after numerous water witching attempts -- that stuff drives me nuts, but I let 'em do their thing). That time they hit it, 180' with close to 10GPM capacity. The record around here is a yield of 60GPM. They couldn't believe it, but the darn thing did indeed pull that much. They didn't use anywhere near that much, of course.

    So I get to looking at the general area where the leak is. It was right at the boundary between the old house place and the field, heading slight uphil with a little ridge/berm there. There is brush and some little trees growing all around, and there's a little cedar tree that had popped up the closest to the leak area.

    So I get the tractor with the front-end loader on it and dive right it, hoping to save as much manual digging as possible. As it is going uphill slightly, I've got a good angle to just, well, dig right in. And before I know it, I've liberated the quagmire/mush and am stuck but good. By that time, my father has ambled down there, and we get a bigger tractor to pull it out. It's pushing 5PM by then and some neighbors are driving by coming home from work and all stop by. To "help" (more like run their mouths). So it's a convention by then.

    Turns out that right here was where the old line to the old burned down house was. They ran it up, then rook a right hand turn to the old house. My father (who had forgotten most of what he'd done) came in with the new line right there, and put a elbow going down, to get it down deep to run across the field. So there was sort of a little PVC "pipe tree" right there. And that's where that stupid little cedar tree decided to run a big root, which grew and grew and finally cracked it.

    In the mire, I found an old 3/4" ball valve, that was an old remote cut-off for the old house. It had got buried and forgotten somehow, but I also found the remnants of the old chimney liner that was used. They make a perfect little "box" for an underground valve. But it was in good shape. Today, I cleaned up and it was still good. It was brass with a stainless handle and the darned thing was as good as new.

    That little tree is just in the way, and so I hook the chain to it and yank it out with the big tractor. That breaks off the "pipe tree" as the root comes out, and water starts pouring out. I'd cut the water off at the well, but hadn't cut it off at the houses. It hits me its probably siphoning out of the water heaters, so I have to run back and cut the houses off. That slows it to trickle, but with 1500' full, it keeps coming.

    It's past 5PM, and it hits me I'm gonna need some couplings and a piece of pipe. The big box stores are still open, but the hardware is closed. So I run back up to the shop to see if I've got any 3/4" PVC couplings (he transitioned to 1" for the run across the field, but the break was before that. If I'd needed 1", I would've been out of luck. I had 3 of them, and several pieces of 3/4" pipe all long enough to do the job.

    There was nothing to do but buck my ears and get down in the mud and cut out the old broken section and put in the new. One of my neighbors decides to help me with the final joint. You need flexibility to put in a piece like that. PVC will do it, but you need enough length on both ends. So a little more digging in the mire to expose enough. Now, measure the length (with my thumb at the spot) and take off a little for play in the couplings. Problem was that water flowing back. THe glue I had wasn't the "good kind" that will work wet. The well side was dry, but the house side was still trickling and would probably keep trickling for hours. So I glue the coupling on the dry side and decide what to do.

    I hold up the other end, bending it enough to stop the flow enough to wipe off the outside and get the coupling glued on. Now the problem is getting the replacement piece in between. So I get the idea of getting my air tank, blowing the water back up the line, then gluing it together fast.

    One of my neighbors, name of Mark, decides to help. I'll get glue on the mid piece, then he'll pick up the house end and I'll blow up through it, then I'll quickly get the piece in.

    We get started, and when it's time to glue the piece in, both of us bend down hard, bang our heads together and then fall over backwards in the mire. Both of us get up mad as heck, but everyone around starts laughing their rear ends off, and then we both start laughing. Time for a do over. Big time. Water has already started coming down again, so it's blow it back and reglue. This time we get it together. It's got the slightest buck to it -- a bit too long.

    So I wait a minute and then turn back on the water at the well house. It holds pressure. Job completed. I'm going to have to let it dry out for a day or two or three before I cover it all back up, but there it was.

  14. #14
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    I know, too late. But I'll post my suggestion anyway.

    With an uphill pipe, I'd suggest plugging the lower end, fill up with water from the top end, connect a compressor to the top until the pipe above the leak is empty of water.

    Open the bottom end and measure how much water comes out.
    Divide by pipe cross section area should give how far from the well the leak is?

    Peter

  15. #15
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    For future reference. Instead of getting an expensive stethescope, you might pick up a telephone microphone from Radio Shack (it attaches with a suction cup and picks up vibrations from solid objects instead of air), run it into a portable amplifier and then a headphone/earbud.
    Et tu BAUT? Quantum mutatus ab illo.

  16. #16
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    Actually, the mechanic's stethoscope wasn't all that expensive, roughly $10. As I said, "el-cheapo" The drug stores (CVS, Walgreen's) around here carry doctor's style stethoscope in the el-cheapo range for them, roughly $20/$30 - $50. They can get expensive, however, several hundred bucks for the fancy ones.

  17. #17
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    Quote Originally Posted by publius View Post
    Actually, the mechanic's stethoscope wasn't all that expensive, roughly $10. As I said, "el-cheapo" The drug stores (CVS, Walgreen's) around here carry doctor's style stethoscope in the el-cheapo range for them, roughly $20/$30 - $50. They can get expensive, however, several hundred bucks for the fancy ones.
    I can recommend the mechanical stethoscope, have used one for many years to diagnose bearing noises, creaks and failures in mechanisms including cars. You can hear transpiration bubbles in trees, water drips as in this case, hours of fun.

  18. #18
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    Glad you're sorted, by simple probing.
    Because I was going to suggest dowsing. Yes, searching with a hazel twig or some coathanger wire.

    I know; completely unscientific, one for the Contrary Theories Forum, and I was thoroughly sceptical until I called a drainage engineer to deal with a blocked drain. Our house is on a corner, the drain could have gone in one of two directions to the main sewer pipe in the road, he wanted to know which. Before I knew the answer, he had me walking to and fro with two cut pieces of wire in my hands, until consistently they moved, along a line that marked the drain.

    I still think it's baloney, how can I, a man of science, believe otherwise? But it works!
    John

  19. #19
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    Quote Originally Posted by JohnD View Post
    Glad you're sorted, by simple probing.
    ......
    Because I was going to suggest dowsing. I still think it's baloney, how can I, a man of science, believe otherwise? But it works!
    John
    Yeah, most all of the well drillers do dowsing, as well as some plumbers and old timers. Around here the term "water witching" is what it is most often called, with the two L shaped metal wire rods being the most popular device, although some swear by a forked peach tree limb.

    There have been various studies of this, and as far as I know, every serious test done under proper controlled conditions yields results no better than chance.

    But at any rate, "water people" of various stripes will use it. Just about any time someone drills a new well, one of the drillers will be seen walking around with his two rods and when the cross to his sastifaction, that's where they'll drill. Just for fun when I get the chance I ask them to explain how it works and some of them can be quite a hoot.

    Another one I love is "moon lore", with the phase of the moon being some important variable in various tasks and processes. For example the moon "has to be right" to cut firewood or lumber. The moon has to full (or it is new) to dig post holes according to some, otherwise the dirt won't do right somehow or another.

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