Trapped main drain line.

[Erby]

Beats me! The ABS drain line went to the rear of the crawl space and disappeared into the ground.

Image Insert:

62.44 KB

Image Insert:

60.76 KB

[Bain]

The house may have been on a septic system at some point. When that's the case, the old drain is typically filled with concrete. Why someone would connect an out-of-use septic drain to a sewer drain is beyond me, but of course who knows what was going through the plumber's head?

Maybe he was conscientious enough to know the original drain shouldn't remain open, but didn't feel like running out for a bag of concrete.

[Erby]

Nah, John. I don't think so. House is over on Pasadena about 50 years old, fairly close to the road. Septic would have had to run to the back yard.

ABS is newer added to the system.

[fqp25]

Originally posted by Erby

The ABS drain line went to the rear of the crawl space and disappeared into the ground.

I would think some kind of exterior drainage system, with a pump somewhere, but from the picture the ABS doesn't look supported adequately to hold the amount of water that is trapped there.

Maybe like Bain suggested, they're trying to connect an old septic connection so any gasses goes into the main sewer and could vent through the house DWV System.

Frank