Snaking a Clogged Bathtub Drain through a Drum Trap

Things have been a bit quiet around here on the blog lately, but I assure you I’ve been keeping busy. Why just today I did some plumbing! I plumbed all sorts of things!

Ok, just one thing. We went on vacation for 10 days over Christmas and when we got back, our bathtub was completely clogged. I’m not really sure how a bathtub clogs while nobody is around to use it, but ours did.

Normally you’d be able to run a drain snake right down through the bathtub and be done with it, but that wasn’t really possible with our old tub for two reasons. First, we have an old-timey drum trap rather than a modern p trap, which generally doesn’t allow a snake through. Second, our tub has an old-timey pop-up drain that also doesn’t really allow a snake through.

Here’s what we were dealing with:

Old-Timey Drum Trap on Bathtub Drain.
Old-Timey Drum Trap on Bathtub Drain.

A lot of folks recommend just getting rid of the drum trap altogether and replacing it with a more modern P trap. But I wasn’t confident I could do that without opening a can of worms that I didn’t want to open right now. I just wanted to be able to clear the pipes without having to replace them right now.

Theoretically, the top of that cylinder just unscrews from the rest of it. However, a quick google search turns up dozens of accounts of people who weren’t able to get the top off because the threads were all rusted shut. My experience was similar. I pushed and shoved on it as much as I could, but it wouldn’t budge. The previous owners of the house left some Liquid Wrench, which I applied liberally, but no luck.

Liqued Wrench from the 70's or Something.
Liqued Wrench from the 70’s or Something.

Again, I turned to the internet, and people recommended using a reciprocating saw to just cut the top off. I also found a few recommendations to drill a 2″ hole in the top, but cutting the top off just sounded easier. And it was. It took me about 2 minutes to saw the top off the trap. I was worried that it would be difficult to keep the saw from riding up or down, and I’d wind up with a jagged mess, but the blade just seemed to guide itself and I had a smooth cut with little effort.

Open Drum Trap
Open Drum Trap
The underside of a Drum Trap after it was cut off with a reciprocating saw.
The underside of a Drum Trap after it was cut off with a reciprocating saw.

After I had the cap off, it was simple to run a drain snake through the pipes. And when I say “simple”, I mean easy, but that job totally sucks because when the drain snake starts spinning, you are literally flinging poo around the room.

Anyway, after the drain has been cleared, the only challenge is trying to figure out how to cap off the top of the drum trap. Since we cut the old cap off, it’s not as simple as just screwing a new one in place. A lot of folks on the internet recommended using a rubber test cap. I used a 4″ cap, and it was just a little bit large, but it was simple to just cinch it down.

Rubber Test Cap on Drum Trap
Rubber Test Cap on Drum Trap

Success. This set-up is water-tight, and still allows easy access into the drum trap in the future.

I’d recommend this strategy to others if they are in a similar situation and want to be able to clear the pipes without having to replace them.

11 thoughts on “Snaking a Clogged Bathtub Drain through a Drum Trap”

  1. Reuben,

    That is an ingenious fix. My aunt has a similar fix that needs to be done with old pipes, but it would require replacing a large section of the waste pluming system (including the central stack which is pricy). Thank you for sharing your experience.

  2. I have a trap that will not budge. I might have to saw off the top myself. only problem is that it is flush with the floor. What a pain.

    1. I saw some websites recommending that you could just drill a 1″ hole through the top and use a screw-on rubber plug to seal it up again.

      Good luck.

  3. Hello, Your page came up as i googled for pics as i’m searching for answers. My problem is the drain pipes and drum trap for my shower are in the slab floor. During our remodel the bathtub was removed and drain centered in the shower but this created a slow drain. Problem #1; A 2 inch drain should be used for a shower but i don’t think that happened. Problem #2; Because of the drum trap, we can’t have it snaked. Biggest problem of all is we may have to bust up the entire floor to fix this properly.
    I’m not sure if you can send me any words of wisdom. If not that, then at least some kind words of condolence. I feel better already relieving my conscience of these troubles.

  4. So, instead of sawing off the top of a drum trap and capping it with, at best a temporary stopgap, why not just replace it with a snakeable PVC P-trap? Am I missing something here?

  5. I too have this problem. My bathtub drum trap is buried in concrete, with no visible cleanout cap (this is the way it has been since it was built in 1928). Is there any way to clean out the drum trap without a cleanout cap?


  6. what a help!! i searched around looking for a fix to a tub thats either clogged or frozen which cant be snaked because of the trap. I decided to see what the drum trap looks like, to see if if couldnt come up with Some idea… and here was the answer! Thank you!

  7. Seems like a reasonable semi-permanent solution, but my method of choice for problems like this is to just drill a 3/8″ hole wherever I want to insert the snake, snake it out and put a rubber-lined clamp over the hole. That would probably work on a trap like this if the hole were on the opposite side, up just a little from the top edge of the exit pipe, so the snake could be angled right into it.

  8. You mention this is water tight ~ but is it airtight? Sewer gasses are considerably smaller than water and escaping sewer gas is a far geater safety issue than runaway water.

    Also, pretty sure that’s not up to code, so if you want to sell or rent a house, this “fix” would need fixing.

  9. Code requires the drum trap be air tight, not just water tight. What you have done is OK for a short term emergency fix, but you have to rip out the trap since there is no repairing it now. If you plan on renting or selling the house, you might as well bite the bullet and get it fixed right. Since the piping is black iron, it should not be too expensive to replace the trap with a P-trap.

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