I have a drain in my garage floor. I've never worried about it too much, but with some heavy rains recently I discovered it doesn't work.

It appears to be clogged with lots of dirt, pebbles, and leaves. I tried pouring a bunch of water down it to see if I could find the exit, but could not.

Would this drain go to the sewer? If not, what can I do to unclog it? How can I figure out where it goes?

I've taken a look at this question, but the drain is in the concrete, so digging it up is out of the question. Also, it appears -from jamming flexible tubbing into it- that it gets clogged almost right away, so I don't think snaking it will tell me anything.

Any help is appreciated.

pic of drain, grate removed: Hemisphere base with the drain going straight out of the side. All that dirt is left over from my attempt to use a plunger on it.

enter image description here

  • A picture might be helpful.
    – Tester101
    Commented Oct 9, 2013 at 16:26
  • True, I should have snapped one before posting. Will make an edit when I get home tonight. It's a circular drain, it's got a hemisphere for the bottom and a pipe that goes out the side of the hemisphere, not the bottom. Commented Oct 9, 2013 at 17:16
  • Any idea how old the drain or the garage is? This might help determine which type of drain you have based on what was code at the time of installation. Is the drain Plastic or metal?
    – mikes
    Commented Oct 10, 2013 at 2:03
  • The house was remodeled a few years ago and I'm pretty sure the original house was built in the 80s. Commented Oct 11, 2013 at 3:18

3 Answers 3


Your garage drain could go anywhere--it could be tied into your septic system or sewer connection, or it could go to a separate exterior drywell or leach field. It could even head into a sump pit to be pumped out by a sump pump. Its impossible to know without a whole lot more information about your specific circumstance.

As to how to unclog it, your best bet may be a high-pressure water jet snake.

jet snake

These can be rented from tool rental outfits, or you could call in a professional. They tend to be better at removing sandy-type clogs than conventional drain snakes.

  • I was wondering if it could just go into the dirt somewhere... I assume that the main function would be for snow melt in the winter, so a very low volume of water. Commented Oct 9, 2013 at 17:20
  • If it went into the dirt somewhere I would hope that it was at least terminating in some kind of a drywell (underground surge tank) or leach field.
    – mac
    Commented Oct 9, 2013 at 17:28

This would depend on what type of drain it is, there are long trench drains and circular standard drains...ASsuming it's circular...

I had to do this in my bathtub, upstairs in an apartment. I would say it's generally the same concept, as I had no idea what was underneath, so my only approach was from the drain itself.

I had to put a rag over the part under the faucet to stop the air from going out there, but aside from that...

I would just try simply plunging the drain, assuming the hole is small enough to fit inside a plunger hole...you're going to be applying enough pressure to push the clog through, follow that with a bucket of water. Might take some trial and error. Might want to pour the water first so that if you do push the clog down you notice by the draining of the water....otherwise might be hard to tell if anything moved.

That's the first step. Chances are if you live in a city there is a main sewer line somewhere nearby that your pipe feeds in to.. If not it's possible it just filtrates out into the lot underneath or around you . You mention the clog stops the flow right away which would tell me something is preventing it almost immediately near the surface of the drain. Remove the grate, and plunge that sucker!

I would also check and see if from any other point does the clog effect the plumbing of the house, is perhaps your toilet slower to drain or bathtub? this could be the point where the pipes meet up, but they usually feed into larger pipes to prevent the clogging issue.

Hope this helps!

  • 2
    the OP might get lucky, but a plunger is unlikely to be effective at unclogging the kind of blockage that would slow an exterior-type drain. You're not going to plunge away lots of accumulated sediment. Plungers are great for too much toilet paper, not so much for piles of dirt and leaves.
    – mac
    Commented Oct 9, 2013 at 16:28
  • I did try a plunger, which didn't do anything. Commented Oct 9, 2013 at 17:13

Be aware, my situation sounds the same, same drain, same back up.same year home. Plummer here with a camera and noticed drain had no access point installed to main drain. just ground like a rain gutter. washer drains in same line so needs to be fixed due to backing up in home every wash. ( just bought home so just noticed ) cost is $3,500 to repair, will dig up curb and street to install an access point. crappy work builders did in the 80's Be Aware

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