Basement floor drains again

I’m slowly learning more about our basement floor drains. I bought a small pump (a Little Giant PP-1) that sucks and discharges through a garden hose, and it does a wonderful job of pumping the drains out. A short length of hose easily fits down the drain, and I run the discharge into the office sump pump. The drain system holds quite a bit of water — as a point of reference, if the standing water is about 4″ below the top of the drains (a typical situation a couple days after rainfall) it takes roughly 20-25 minutes for the PP-1 to pump them out. This is slightly longer than the PP-1’s 15-minute duty cycle, so I have to do it in two “shifts”.

With most of the water out of the drains, I’m more able to inspect the drains and see how water flows through them. In the back part of the basement, It appears that the 4″ vertical drain pipe goes directly down to a cast iron “T”. If I run a tape measure down the drain, I’m able to get it to go in either direction a good ways. This seems to indicate that the lateral line is directly underneath the drain, and it’s 4″ cast iron. If that’s indeed the case, then that is good news, because it will be easy to get a sewer auger into the line.

What’s still not clear, is where the drain lets out, and why it collects so much water. The line is a good 7 feet below grade. As to the water, my theory is that the people who did the waterproofing in the well room area tied these drains in with that system, and the water from that drain tile is draining through the floor drain pipes. Since the floor drain pipes are plugged up, the water collects until it overflows into the well room sump pump. It’s really the only theory that would account for the volume of water that collects in the drains (the water problems in the well room area are another, totally separate issue…)

Next steps: I’d like to prove the theory that the lateral line is directly under the drains. I think I can do this by running a snake down one drain and seeing if I can spot it in a different drain. Then, I want to empty the drains and observe what happens during a rain storm. That will (hopefully) confirm that the water is coming from the well room and not the other direction. And then finally, I can look into snaking the line, doing a video inspection, etc.