I have a u-shaped pipe coming out of the ground in my front yard. It ends over another larger pipe that goes in the ground. I don't remember water ever coming out but it currently has clear water coming out. Do you know what it is and why water is coming out? See the image.

Looks like a yard drain to me. Probably from a high flood area of the yard or property.

I disagree. Looks more like a vent to me. Are you on city or septic tank? Cheers, Tom

City. There would have been no yard drainage when I saw water coming out of the pipe.

Any idea what the line it drains into is? Check these out and see how extensive it can get.

Residential Yard Drainage - Bing Images (http://www.bing.com/images/search?q=Residential+Yard+Drainage&Form=IQFRDR#a)

Do you have a basement?

Do you have a sump pump in your basement? If you do have a sump pump, can you see where the discharge pipe exits the building or ties into the drainage system? If you do have a sump pump and you do not know where the discharge pipe goes, test the pump by turning it on with water in the pit and see if water pumps out to this spot in the yard.

If the sump pump discharges into this pipe in the yard then I would suspect that the DRYWELL is filled in and needs to be redone or the pipe going to the drywell is clogged...;)

Just my thoughts...

Mark

I can't tell where the drain line goes. There is no clear exit anywhere that I can find. I don't have a basement.

We do have an extensive yard drainage system but that is all piped on the other side of my lot. None of it is near this pipe/drain.

AC condensate drain?

Ok, but you aren't clear if you do have a sump pump. Do you have a sump pump in your house (even if you can't see where the pipe drains of, too?? If you do have a sump pump we can tell you how to test if the water in the yard is from the sump pump (*hint* colored dye tablets)!!

I lean toward the idea that you have no major flood or water build up issues may well be that the previous owners had already addressed them, and maybe talking to neighbors will reveal clues to what has been done in your area. Maybe they have similar piping on their property, and know the reason why, as the lot next to you. Receipts or old permits may also lead you to clues as to why this was done on your property, and by whom, as I would imagine a lot of work had to be done by not just the city, but county in connect services to your area. It will be tedious maybe but beats trying to figure out where your underground pipes are and less expensive than the normal way a specialist would find them.

Landscaping and utility companies are where you reach out to those specialist. They to may have old records as to work done and why. I don't know where you are, or the makeup of the land, but what leads me to think this is part of a yard/property drainage project is that you observe clean water from this pipe which indicates functionality on some level, and you have a similar project on the next lot.

Bet your other neighbors do too. Ask them. Comes back to do you have a sump pump which I doubt at this point, since you have city water, AND sewer services. Am I correct?

My guess, without digging it up, would be either a AC condensate drain or a water heater T&P drain. Cheers Tom

Looks like to me that it may be a fresh air vent for a house trap connected upstream of the trap, they were/are used to access the main line leaving the house for snaking purposes. That is my guess... old houses in New York, east coast, etc... now days the traps are often removed as each fixture should be individually trapped, thus protecting the interior of your home from the evil sewer gasses!

It can be pool pump drain pipe or as Mark said, sump pump discharge ( from yard, from around pool, from basement floor drain etc ). Have you ever see water running through it ? If you see it discharging water, try to quickly scope your house to see what is On and Running at that exact moment. Let us know what you've found out. Back to you. Milo

It was the backwash line from the pool. Thanks for everyone's help!

Glad you solve the mystery. Thank you for the feedback. Always nice to hear. Good luck, Tom