Plumbing inspection not high on RVers’ lists


By Russ and Tiña De Maris

If you’re old enough to remember The Hardy Boys or Nancy Drew mysteries, perhaps you’ll recall “The Mystery of the Crappy Crapper.” No? Okay, so we made that one up. After all, most of us were born after the advent of indoor plumbing, and we all just take “the throne” for granted. Flush it, forget it.

But then Chuck Woodbury stumbled on a bunch of complaints from RVers who did, in fact, have crappy crappers. When Frank, Joe and Nancy all got together and did their detecting thing, they found the mystery wasn’t so mysterious in itself – it seems that some RV manufacturers don’t have the magic bowl drop its contents straight into the black water holding tank – rather, they send the stuff by a circuitous route by way of bends and pipes before finally allowing it to dump into the tank. The real mystery to be solved was this: Why on earth is the path for the poop particularly poorly positioned?

The answer seems to lie in the old adage: Money talks. When RV manufacturers hit upon a floor plan that’s popular (read that: “sells well”), design considerations fly out the window. Never mind if you have a toilet that, in the words of our reader, Margaret B, “spews contents up and out in a giant bubble onto the floor and walls.” So what if, “The toilet room is on the passenger side and the tank is more on the driver side,” which is Joanie T’s experience. “I was blamed for using too much TP!” she relates. “But after cleanout we discovered the turn in the pipe.”

This whole situation seemed so ludicrous, but at the same time, devastating to toilet sitters, that a poll was immediately undertaken. Question: “On any RV you’ve purchased did you check the toilet’s plumbing design beforehand?” Here are the results: A whopping 86 percent said, “No.” And why on earth would you, anyway? We come from the “flush it, forget it” generation. And yes, 14 percent of you actually did check out plumbing design in advance of purchase. From our own experience, of the five RVs that we’ve owned, all of them were of the “direct drop” variety, and happily, we’ve never had the misery of a clogged toilet so, of course, we don’t make it a point to inspect plumbing design either.

But there are plenty of readers who’ve had problems with this convoluted design. Doing an RV remodel job, Les found this: “There were two elbows in the waste pipe between the toilet and the black tank . . . Removing the black tank I found that the waste pipe protruded into the tank approximately three inches, causing the toilet to flush slowly while the tank was only half full.” Tom Hudson relates, “My previous [fifth wheel] Mackenzie Starwood had bends in the sewer line. Fought it for eight years.” And Paul Goldberg adds, “2004 Southwind had a 45 degree slant from toilet to black tank. Over eight years of ownership I had learned two things: 1) How to manage it so it didn’t cause a lot of problems for us, and 2) I didn’t want to deal with it ever again.”

So just how do you “manage it” when the bends in your “sewage river” cause you grief? There were a few suggestions. “I keep a four foot piece of cut garden hose hidden in the bathroom,” confesses Jim K. “Because every once in a while, toilet paper will get stuck there.” Jim rams the hose down the toilet to clear the two-inch 45-degree elbow in his Winnebago Outlook.

The old “ram it down” solution was highlighted by readers, including Bob P., whose 1999 Bounder abounded with a 90-degree elbow in the black water line. “Had to have a plunger handle to break the waste into smaller parts to get it to go down.” But that wasn’t the only “answer” to the problem. Some may call it extreme (or perhaps, “too much information”), but Bob adds, “We ate a high fiber diet to keep waste flushable.”

If a dietary regimen of whole grains, raw vegetables, and Miralax just doesn’t seem appetizing when trying to keep the old poop chute running, Thor Industries has a few suggestions. Mind you, Thor is the manufacturer of the Thor Ace, one of the RVs that seems to come in for frequent criticism for backed up toilet plumbing. Maybe it’s a case of “treat the symptoms, don’t cure the disease,” but Thor recommends:

“Toilet Tank Wand: You can find these at camping stores or online. They connect to your bathroom faucet with a flexible hose and allow you to spray through the line and break up the clog.

“De-clogging Chemicals: There are plenty of de-clogging chemical options that break down the tissue that gets stuck in your toilet line. Follow the directions on the chemical packaging carefully.

“Water: Bring a pot of water to a rapid boil and carefully pour it down the toilet. Repeat several times as needed and let the water sit overnight without using the toilet.

“Ice: Fill the toilet a third of the way with water. Add ice until the bowl is completely full. Flush the ice and drive your RV around to distribute the water. Continue flushing with extra water and ice until the line is clear.”

Be careful with that hot water trick. Sources suggest that straight boiling water could lead to toilet damage and recommend using hot water that’s not quite to the boiling point. And we’re not sure that we’d necessarily recommend “de-clogging chemicals,” either. If for some reason, the stuff ‘blew back’ at the wrong time, it could be mighty uncomfortable sitting for a while.

Aside from recommending that you flush with plenty of water or even, as some do, dump the toilet paper in a covered container and don’t run it down the drain, we’re pretty much flush out of ideas.


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Amazing that this problem even exists. Common sense has left the building if they have built even one where its not right over the black tank.

I am so sorry for anyone afflicted with this. It has gone so far down hill it makes me wonder where it will stop.

we bought a 2004 model in 2015. We shopped for 3 years before we bought. We decided to buy Pre Crash, regardless of putting us outside the west coast 10 yr rule .

Pre crash provides for buying units that at the time were being made during the race to the top. when they were actually competing for buissness. In the Rv world, it provides the best Chance at getting something solid.

Anything Post crash, is built during the race to the bottom 99% of time. And you can apply this to just about anything really. Vacuums, cars, houses, rvs, electronics, ect…

The answer is buy used. Buy pre crash or further back. make your buys based on reliance and future servicability, not based on what RV park you can get into. Make your buys based on preserving your future disposable income.

Its not reasonable to buy such a large purchase like an rv and end up not being able to use it, and not being able to fix it yourself (because you have no money left after making that payment) and having no one being accountable for the manufacturer defects. Its just not reasonable. But it is todays reality when it comes to buying an rv.

A good used Rv -Yrs 1995-2008 model yr(because 2008’s started being made mid 2007 and ended mid 2008, with the 2009’s coming out in july 2008) of whatever variety you are after is a good starting range for looking.

Captn John

My wife asked “why replace a nearly new toilet?” After reading the problems associated with Thetford toilets in new campers it became a preventative measure. A shiny new Dometic 320 for my hiney and one less possible crappy situation.


All those suggestions on how to un-clog your drain line is at best a bunch of crap!! What I mean is the FOOL who designed it, they knew it wouldn’t work & they also knew NO one would actually look down the toilet, or even know what its supposed to look like, I didn’t, but mine is all most straight, can’t even fathom any toilet having 2 bends in it, let alone a 90 degree one. What were they thinking.


You can find the Biffy here
Call us first 877 787 8833 Toll free to insure you toilet will work with the Biffy.
We have been selling them for 12 plus years and they work very well for the purpose intended, keeping your not so direct drop toilet piping clear is a big bonus.


I installed a Buffy Bidet to our ceramic toilet so we use little to no toilet paper.