So it's 2020 and I found this forum while searching for a way to clear our french drain in our basement. It's a 4" PVC sewer pipe (not corrugated, but actual white PVC pipe) and it's always flowed well. Unfortunately tonight I heard our radon fan sucking water (it's raining outside). I knew immediately it meant the water level in the french drain hole had reached the bottom of the radon pvc that's placed in the Plexiglas cover.
I called roto-rooter and they said sometime in the next 4 hours they could come out. I had to wait for a call within the next 30 minutes though to confirm the appointment time. It's already 8pm here right now. Our french drain run is about 250 ft. I called a plumber friend to seek some basic consul as to how much I should expect to spend. He said a night call, and a 250ft.+ run? $1000 easily. That just *****. So while waiting for my callback, I got my 6.5hp shopvac out and tried draining the hole. No such luck. It's still raining and it's filling up faster than my 16gal. tank can **** it up and I can empty it. Also, we're on a septic system. I can't go flooding our septic system with an abundance of water. So I reversed the shopvac and attempted to force air. (My plumber friend I could try a plunger.) I figured constant forced air from a shopvac would amount to the same. WOW! It was like a stick of dynamite went off in the water. The air went in the pipe, but it came back out with a VENGEANCE!!! Must have shot up 4 feet from the french drain hole!!!
The final try would be to take my shopvac out in the woods (I live on 11 acres) to the other end and try to apply some negative pressure and **** it down the line. My theory was that this may work better because that's the natural gravitational flow direction anyway, and SOME water was getting through - albeit a very small trickle, but still, I was hoping it would be enough to entice a clog free. Problem is how to get electric 250 ft. into my woods? I took a small generator we have (1200w) with me and my shopvac out in the woods to the end of the line. I tested the shopvac first though to make sure the generator could handle the load (I've done enough dumb things in my life at this point, I know better). I also made a makeshift cover for the 4" PVC pipe out of a coffee can cover and drilled a hole for my shopvac hose into it, to make the best seal I could. I took foil tape with me for added ingenuity needs. My wife came out with me with 2 flashlights.
We hooked up the shopvac, placed the makeshift coffee can cover/lid against the line and promptly found out it was not wide enough. While it was wide enough on the house end, the end of the line pipe flares out and is slightly wider. So I taped the hell out of the PVC pipe 1/2 way across with foil tape - 5 layers. I placed my coffee can lid/cover and hose over the pipe and held it there for as long as I could. At first nothing changed. I placed it back over after taking it off the first couple times. This time I held it there for a very long time. Suddenly some more water flowed out - but then a tsunami of water rushed out, and it was super brown.
I'm happy because the line cleared. Unfortunately I know the brown water likely means there's some root intrusion along that 250ft. run and as a result dirt is getting into the line. It's going to get worse with time, not better.
Clear for now, but I will now think of how I can inspect 250ft. of drain pipe that's buried at least 5-6 ft. deep in super rocky soil. :/
I'm thinking a wireless camera attached to a small RC car (with a rope attached so I can pull it back) and drive it up the line to look at what the interior condition is.
Fun projects!
Anyhow - +$1000k or more in my pocket!
Sharing in hopes someone else might need some ideas in the future themselves. (Oh, and my plumber friend - he owns a gigantic shop with big trucks and industrial equipment - he warned me that beyond 300ft., a snake looses it's effectiveness (torque) and there may not be much that can be done - at least with his equipment. Was sounding like it was going to be VERY VERY expensive!!!
So we extended it with some leftover pvc pipe and all is well.