When to call the plumber about a blocked drain

When plunging the toilet made no difference, and because we already suspected a main drain or system problem (all drains were slow), we knew we needed a plumber to help with further diagnosis of the drain blockage.

We suspected a blockage between the house and the septic tank because the septic tank and seepage pits were pretty new and unlikely to be blocked themselves.

The plumber obliged with the next two steps in diagnosing our drain problem: first he opened a convenient coupling in the waste line in the basement. You can see where we made this opening in the photo at left.

This would give an easy access to the drain line nearest to the toilet itself in case the blockage was nearby in the home. Opening this connection was diagnostic for a second reason as water spilled out of the coupling as it was disassembled. This told us that the waste line was blocked sufficiently to hold a large volume of water backing all the way up into the home.

Photograph of backup drain spillage clues on a washer drain.

That diagnostic fact explained why we saw evidence of drain backups coming out of the open top of the clothes washer drain line where it spilled onto and disturbed dust atop the main waste line nearby. You can see evidence of drain overflow on the washer drain piping in the photo just above.

By simple visual inspection, following the pipes in the home, we could see two interesting facts: first a main drain and cleanout were located in the house rear foundation wall, and second, the toilet drain passed separately through the same rear foundation wall just a few feet away.

While we never bet big on where buried drain lines run, the geometry of the basement of this home made for a small, cramped space.

It seemed likely to us from the angle of the pipes and the ultimate destination of the piping (a septic tank downhill in the rear yard), that the two lines joined outside the home, n