Here’s a post with some yucky photos for you: Today I cleaned out our P-traps, and I learned a few things along the way!

After almost a year on the road, Ching and I both noticed that our bathroom sink is draining very slowly, so I decided to try and fix that. As someone who sheds a lot, I have become accustomed to clogged drains in my life, and I think it’s fair to say there isn’t a lot of curly hair in Ching’s family…so the clog was probably my "fault”, anyway. That makes it my responsibility to fix it!



Behold: The Spoke!

The first place I checked was the inside of the drain, under where the stopper goes. Sure enough, there was hair in there, so I removed it with one of my favorite tools: an old spoke. Go to a local bike shop and ask them for a half dozen spokes out of their scrap bin. Most useful thing ever.

Anyway, the hair I got from the drain was definitely not enough to be causing our slow draining, so the next likely culprit was the P-trap. P-traps are familiar sights under sinks, toilets, showers, and anything with a drain. It’s a little dip in the pipe that is always full of water. It lets fresh water through, but never fully drains out. This creates a “trap” for gases that want to come back up through the drain pipe when water isn’t flowing down it. In a stationary home, these would be sewer gases; in an RV they are grey water tank gases, and yeah, they stink! Because the trap is a low point, it tends to also collect debris, and if enough debris gets in there, the trap will plug.

In a stationary house, an occasional dose of drain cleaner would be the easy solution for this problem. It would break up the clog and let it be easily flushed down. But that’s not an option for RVs because that drain cleaner would nuke all the organisms that live in the greywater tank and digest yucky stuff. Without those organisms, the grey tanks would start to really smell, at least until they got dumped again.

I did try pouring some grey water tank digester through the trap and letting it sit for a few days. It was time to add more to our grey water tanks anyway, so I thought it might help break down the clog in the trap, too. No dice.

Something interesting about RVs is that their plumbing parts are (usually) “mobile home” components. This means that removing a P-trap is a totally tool-free job, and takes like one minute (In a stationary house, the P-trap might require a large wrench to loosen the nuts). Quick and dirty instructions on P-trap removal:

  1. Get a shallow bowl that will fit under the trap, because water will definitely leak out when you loosen it.
  2. With the bowl positioned under the trap, loosen the nuts securing it to the drain tailpipe and the drainpipe. These are both standard right-hand threads, but one is upside-down. Check out the photo.
  3. With the nuts loose, the trap will drop straight down. The drainpipe side has a beveled connection, and the other side will have a length of the tailpiece which slides into it. This might be long or short, just slide it slowly to avoid surprises, and keep it upright to avoid dumping it out.
  4. Pull the trap and your bowl, together, out from under the sink. Time to dump out the trap and see what joys await you!

Look at the crud on the tailpiece.


This is what came out of our trap:

Hmm, time for a new toothbrush!

Hmm, time for a new toothbrush!

Holy shit, yuk! What is that??? I had expected hair and shaving-trimmings, but the gloop…it appears to be toothpaste...kinda minty smelling, beneath the gross greywater stink. WTF? We use very sparing amounts of toothpaste (gotta stretch those dollars), so what’s with all the extra?

Apparently this is a year’s worth of Tom’s. I suspect that we use so little water when brushing our teeth, that the stuff we spit out never really gets flushed through the trap. When we use this sink to wash our faces or shave, we usually collect the water in The Greatest Bowl Ever, so that water never gets flushed down the drain. This lets us get a lot of mileage out of our grey water tanks, but apparently the price is occasional trap clogs because the only water going down there is a few ounces from tooth-brushing and our hand-washing water.



We could easily change our behaviors to prevent this: Just dump more water down the drain. But we really like how long we can go between dumping our grey tanks (nearly 3 weeks!), so if that means we just have to perform this cleaning annually, it’s well worth it. Normally I’m very interested in preventing problems, but this is one problem that’s so easy to fix, it’s not worth it to avoid.

The Greatest Bowl Ever

I have to tell you about this bowl. For some reason, we can only find them in Asian grocery stores, but they are the greatest things to have, and they cost like $1.50. It’s just the right size and shape for everything cleaning-related. The fact that it happens to fit exactly inside our sink is an accidental awesome bonus. We use it to catch the cold water that comes out of the shower (until it warms up) so we can re-use it, and all sorts of other stuff. Ching describes how we use it to take a low-water bath in her post, When Was the Last Time You Showered? And apparently, it makes a good trap-removal accessory. Maybe we should get a second one?


Follow up

When you clean one trap and it's full of goop, you can’t help but wonder about the others. We just started using the strainer in the kitchen sink drain, but we didn’t used to. So I figured there would be a lot of food in that trap, too. Upon removal however, I found it was quite clean. Clearly the kitchen sink gets enough water flowing through it (3 meals a day plus washing dishes) to keep the trap in good shape. This supports the idea that more flow = clean traps.

We've never actually heard anybody mention slow drains or cleaning P-traps in their RVs, so I'm wondering if we're just disgusting freaks, or if this happens to others. Anybody have similar experiences?


Thank you for making your Amazon purchases through our affiliate link.

Featured Posts