Strange pipe found in back yard under paving stone

[Dirtpig]

I found this while doing some landscaping in my back yard, i moved a paving stone and this was found. it is located about 2ft from the house foundation. and about 1.5 ft from one of the perimeter drain clean-outs. It is 12" pipe and it goes down about 7ft with the bottom 1-1.5ft being water and seems to be gravel or dirt at the bottom of the pit.

Any idea what this is or is used for? I found it by fluke.

Thanks for any advice

 

[phishfood]

Gravel at the bottom seems to suggest some type of soil infiltration drainage system, either a septic drainfield, or a greywater system, for a laundry, air conditioning condensate, etc.

Septic drainfield does not seem likely, so close to the house.

 

[havasu]

I'm curious to find out if this is at a low point of your yard?

 

[Dirtpig]

I would not say it is a low point of the yard. The yard is predominately flat with maybe a very slight grade away from the house on all 4 sides.

It does not have a smell, the water down the pipe seems to be clear. My house is on a town sewer system so i dont think that it is septic either.

Here is a little bit more information. Just over a week ago we got over 250mm of rain in a 2 day period and the 4ft crawl space under my house developed about 3 small pools of water with about a 1/4inch of water in them. the water seemed to be comming up through the rough cement foundation floor. I only noticed this as i was putting the christmas decorations back down there. I called roto-rooter (a drain unclogging company here) and asked them to come and flush my perimiter drains or look at them as i suspected that was the source of the water problem. Sure enough the perimiter drain was completely plugged where it leaves the house towards the town drain at street. He unclogged it and ran the jetter through all the perimiter drain pipes (4 cleanouts around house) and camera'd them and they looked clean. there was a lot of water exiting the pipe after the unblocking >1/2 full on the 4" pipe. The guy said he never saw a release like that before. 5 days later i can still hear the perimeter drain rushing water but not as loud as the first day or two. The guy said he was unable to flush the one side of my home as he could not find the cleanout this side is the side where i found this huge burried pipe today.

Another thing is the side of the house with no visible perimiter cleanout which is also the side with this strange pipe burried is an 12x14ft addition with concrete foundation and 3ft crawl space (inaccessible).

The house is 14yrs old, the addition is 13.5yrs old. i have owned the home for almost a year.

maybe some of this extra info helps you guys, thanks for the advice

 

[speedbump]

Looks like a rope or wire is tied to the rebar, is there something hanging from it. A pump maybe?

 

[Dirtpig]

There is nothing hanging from it, but there may have been at some time.

I did a little more investigating, dug around at the bottom with the longest thing i had which was a garden hoe 7ft long and there seems to be nothing down there but dirt, nothing i can find around the edges leading out or into the side of the pipe. I took a garden hose on full blast to see if i could fill up the pipe with water, i measured the water level before and after about 10min of continuous water flow. The water level came up 4" and then i could hear water running into the perimeter drain (had cap off so i could hear). So i could not pass that point of a 4" rise with the garden hose. I then filled 5, 5gallon pales with water and dumped them down the pipe and water came up almost to the surface only to disipate back to the original level within about 1min. perimiter drain was draining pretty heavily at this point.

So maybe it is some type of tube that was put in to measure ground water level or take ground water for irigation use? i was not able to feel or see a direct connection to the perimiter drain.

Maybe i have really high ground water level on my property?

by the way.. the perimiter drain is still draining but we have had no rain in a week.

 

[waterwelldude]

It looks very new. Going by the looks of the re-bar in there. being that close to water, re-bar will show lots of rust in just a few days. It almost looks like it was put there to de-water the ground while doing foundation work or to install a pool maybe.

Just a thought.

 

[Dirtpig]

waterwelldude. That would make sense because as i said earlier up it is right outside the addition which the previous owner did. Maybe he used that as a means to remove water when digging and pouring the foundation for the addition and just left it there instead of removing it. i wonder why it was left in place and just hidden by a paving stone. wouldnt it be removed?

 

[waterwelldude]

Not necessarily. If that is the reason it is there. It could have been left there for future use. Covering it like that would be a good way to leave it, and hide it at the same time.

 

[speedbump]

It could have been a failed attempt to get some water for the yard.

 

[waterwelldude]

I would almost bet that there is another one on the other side of the house.

 

[Dirtpig]

i will look