Mystery Greywater Drain

chayce

My house was built in 1956 and it has a greywater laundry drain which backs up. The pipe goes out the garage wall on the same side as the main drain and disappears under the sidewalk. My first assumption was that it went into the main drain, but when there is water flowing through it there is none visible in the clean-out connection on my main drain. Then I figured it was a greywater drain to the ditch on the side of my lot, but I can't find where it comes out or dig out the pipe in that direction. It has flow, but not enough to handle the washing machine draining. Other than breaking up the sidewalk, or digging holes all around my yard, what solutions are there to finding this mystery drain? Any suggestions would be helpful.

plumber666

I'd bet it goes to a drywell (rock pit) that is now full of lint and crap. Grab a shovel and check it out. Sounds like the garage laundry room was an afterthought and it would've been easy to do it that way.

jogr

Run a snake down it to get an idea of how far out the drywell or blockage is. Sometimes a T rod (about 1/4" or diameter and long enough to get to the drainpipe's depth) can be used to track the pipe. Start at the house where you know the pipe exits. Just push it in the ground till it hits the pipe. Follow the pipe out the distance determined by the snake.

Daniel Holzman

In the dim distant past, it was common to run greywater out to a drywell. This is no longer allowed in most areas, current practice is to connect the greywater to the sewer line. You may want to do the same.

chayce

Ok, I've decided to dig untill I find where the pipe leaves from under the concrete walkway and then connect it to the main drain and properly vent it. Thanks guys.

Mike Swearingen

If it doesn't have one, it also needs a trap before the vent.
Mike