There is a septic tank somewhere in my backyard, I must decomission it. The sewer pipe goes into the basement floor and historical permits from the 50's sets the depth of a sewer connection at 8ft. There is some chicken scratch that suggests that the cesspool lies 15 ft from the house at a depth of 8 ft. 15 ft is a somewhat odd distance as the requirements at the time it was installed was 10 ft and a plumber saves 5 ft of pipe and trenching if he sticks to 10. My hole is about 8 ft deep at 15 ft from the house and I've found nothing so far. I'm going to do another foot before I start trenching toward ten feet away from the house. It could be that the sewer line was moved when they changed from septic to city sewer. The septic might be going off at an angle which would make this process a whole lot harder. I can't follow the pipe from the house because it's under a concreat slab. All this is so we can build a deck. My hands are like hamburger right now and I hope I find this thing soon. The old cat and the new cat are becoming decent friends.
Hey, just a quick one as I'm on my phone: this is probably mad overkill but I can't help thinking that this is a good use case for many of the techniques mining exploration people use for mapping geological features (exploration geophysics). It's not my personal focus but I think you'd have a good chance of finding the pipe using ground-penetrating radar or electrical resistance tomography (where I live the domestic sewer pipes are plastic but maybe you might have luck with a metal detector too). Some guys that I work with spent some time trying to use these to do realtime crevasse detection and I believe it's the same technique used for archaeological surveys. Whether it's a commercially available service with a reasonable price tag I'm not so sure. Anyway as I said it's probably overkill but it immediately popped into my head so I thought I'd share. Cheers.
Metal detector won't hack it at 8 ft deep. I might have to resort to underground radar if I can't find the pipe. Hiring a company to do the location and dig would cost over $3 k while doing it myself will cost about $1k. The deck is already a significant expense so I'm trying to not hemorrhage any more cash.