Demystifying our basement floor drains

I’ve decided to try to figure out our basement floor drains. My goal is to ascertain:

  • How the drains themselves are configured;
  • Where the plumbing goes;
  • Why they seem to hold water indefinitely; and
  • Why they back up into the basement during heavy rainstorms.

My goal is to either fix the existing drain system (I’m assuming it’s clogged), or reroute the drains somewhere else, like a sump pit. A third, less desirable, option would be to just close the drains up completely. But I’d rather keep the drains around, because (properly working) floor drains provide cheap insurance against flooding from things such as burst washing machine hoses, busted water heaters, etc.

My current hunch is that the drains tie into an old network of underground pipes that also used to handle the rain downspouts. I’ve abandoned most of these in favor of downspout extenders and splash blocks. However, the pipe openings are still there, and they still collect some water in rain storms. Assuming the original piping is plugged up, this could account for the rising water in the drains during rain storms.


Yesterday, I tried sucking some water out of one of the drains using a wet/dry vac and some PVC piping sized to fit into the drain openings. I’d estimate I sucked out around 20 gallons before giving up — much too labor intensive. However, I managed to get the water level down around 2 1/2″, and the water dropped around the same amount in all the floor drains I checked, which seems to confirm that the floor drains are tied together, and that the pipes underneath them are relatively clear. There’s still too much water to see all the way down to the bottom of the drain, though. Interestingly enough, after 12 hours or so, the water level had crept back up around 1/2″. No rain during that period, and I’m relatively sure it’s not ground water — our water table is not that high.

Next up, I want to get the drains completely free of water, and try to figure out where the pipe exits the drain. Apparently there’s quite a bit of water down there. So, I’m going to need a better (less labor intensive) way to get the water out. I’m going to try a drill powered pump, with the discharge going into the sump pump pit. With the drain free of water, I’ll try to get an idea where it goes, and see if there’s any chance of getting a snake down there.

With the drains empty, I’ll then try flooding a couple of the downspout pipes outside, and see if any of the water ends up in the drains. That will tell me whether they all tie together. At that point, can make some decisions as to what to do next.

Aah, the joy of old houses. Stay tuned!