Who do you call for leak detection services?

May 12, 2014 1:39 PM

I've got an automatic backyard sprinkler system that has sprung a leak, but I have no idea where or how. I'd trust the gardening company that installed it, but they weren't very good at previously finding leaks in their own work (they installed it). Are there professionals that use modern tools to solve these kinds of problems? Should I just call a plumber or HVAC guy or is there someone more appropriate?

Previously, our leaks were really obvious, we'd see a wet, soggy spot in the lawn or garden area, the gardeners could dig it up and patch the pipe. This time I can't tell where the leak is happening so I think I need someone more professional to figure this out. This is a pretty bad leak, we saw our water bill shoot up by $100/mo late last Fall when we were barely using the system.

I imagine there must be ways to figure this out with high tech, either dyes or isotopes or thermal imaging cameras or something (or maybe I watch too much CSI). Should I go with the gardener who will probably dig a zillion holes to find it, or are plumbers good at this too?

posted by mathowie to Home & Garden (3 answers total)

You can google up "sonic leak detection" for your city. They connect high pressure air to the line and listen for the hissing air leak. However this service will probably cost you several hundred dollars.

You might be able to find this problem yourself and save a few bucks.

1. First make sure the leak is in the irrigation and not somewhere else, like toilets. To do this, shut off the main valve coming into the house. Go out to your water meter and look for any movement in the tiny wheel. If you see any movement with the main valve to the house off, then the leak is in the main line between your house and the meter.

2. If not in the main line, then determine if the leak is inside the house or outside in the irrigation system. Turn the main valve to the house back on but turn the value supplying the irrigation system off. Don't just disable the irrigation system. Turn off the main mechanical valve supplying the irrigation controller. Check the meter again for movement. If it is leaking with the irrigation off, then the leak is inside the house, most like a toilet.

3. If the leak is not inside the house, then you can try to narrow down the leak outside by turning off the the individual valves for each irrigation zone to figure out which one is leaking. Check the meter for each test.

4. If you have a map for you irrigation system and know which zone is the problem, you have reduced the area of investigation. It might be the control valve for that zone or it might be in the exterior plumbing.

5. If you can't find an obvious soggy area, turn off the leaking zone for a week, a month or whatever until the grass starts to dry out. Then turn the leaking zone back on and in a few days, the leaking area should start to magically green up.

It's just like finding software bugs. You try to isolation the problem to smaller pieces and then you run tests on that area to find the problem.
posted by JackFlash at 2:22 PM on May 12, 2014 [1 favorite]

Actually, I think it's done with stereo microphones. Our plumber said that the specialist he recommended would find the leak or we wouldn't pay. I think it was $300, in suburban Northern California. However, our plumber first worked to isolate the leak, by installing a shutoff valve between the supply and the irrigation system. When we were able to narrow it down, I walked quite a bit between the supply and the meter and finally found the leak without the aid of high tech. Our leak was also costing about $100 per month additional, but we found it after only one month. It was roughly 500 gallons per day, about 2.5 feet down, and so eventually the dirt got wet above the leak enough so I could spot it. If you still can't see wetness after several months, it's probably draining somewhere, so you'll probably have to call the leak detector. Get a recommendation from a plumber, not a gardener. It's worth the money not to leak another 100,000 gallons into a culvert under your house.
posted by wnissen at 2:24 PM on May 12, 2014

If JackFlash's test tells you it is in the irrigation system, I would try opening the irrigation system downstream of the one-way valve and inserting a fluorescent dye tablet, waiting a few days for this UV flashlight to arrive, and then going out at night to see what you can see.
posted by jamjam at 5:26 PM on May 12, 2014