Wednesday, November 30, 2022


On any RV you’ve purchased did you check the toilet’s plumbing design beforehand?


In Issue 859 of the newsletter, we discussed the inefficient, even problematic design of some RVs’ plumbing systems, where the piping from the toilet to the holding tank caused problems when flushing solids.

With any RV you purchased, did you ever inspect the plumbing’s path from your toilet to the holding tank?

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4 years ago

Did a factory tour of Phoenix Cruiser. Not only did we see how tanks and pipes were run but all the wiring, ducting, venting and everything else inside walls, floors and under the frame. Great design and well built product. Very happy with our 3100. In 2016 went 15,000 miles to Alaska and back (FL), NO Problems!

4 years ago

I’ve looked at all 5 of my fifth wheels. From the first one, where the discharge was so low to the ground that it caught and broke while backing into a drive. (No curb cut!) The last one was discovered while replacing the tub with a sunken corner shower to enable wife to shower easier. During the shower bath renovation I found two problems to fix. There were two elbows in the waste pipe between the toilet and the black tank. I removed the tank to fix the pipe. Removing the tank I found that the waste pipe protruded into the tank approximately 3 inches, causing the toilet to flush slowly while the tank was only half full. Yes there are all kinds of “problems” with both supply and waste water systems in RV’s.

Captn John
4 years ago

I have always had water in the FW tank and a hose connected as well for PDI. 1st item, turn pump on and complete PDI, then water. Hot/cold ~~ nothing leaking? That included the toilet, but never thought there would be anything but a straight drop into the tank.

4 years ago

Many coaches that do not have a direct drop from toilet into the black tank have a vacu-flush toilet.

They work quite well, but do not like 2 ply toilet paper. Works much better with single ply – like Scott.

Scott Krugerud
4 years ago

I never checked the black tank but certainly I will on our next camper.

Kyle Nelson
4 years ago

I want to know what women designed the toilet we have in our “luxury” 40 ft Heartland that my (parts) hit the bottom of the toilet when I poop?

4 years ago
Reply to  Kyle Nelson

Why are you blaming women for poor design when you know darn well a guy probably designed that flaw. Much like guys have designed most of the flaws that get brought up regularly on this website.
I’m betting if they ever let a woman design an RV that quite a few flaws would be corrected.

4 years ago
Reply to  squeakytiki

I agree totally.

Kelly R
4 years ago

Yes I checked. Roadtrek Ranger has slight bend but right over tank. No problem flushing. Drains on opposite side of the coach and pipe is only 4 or 5 inches off the ground so when emptying tank it is sometimes a level or uphill situation. (Did not pay attention before purchase.) Not much “boondocking” with waste pipe so close to the ground.

Susan Dooley
4 years ago

I use a flashlight to look down the toilet, problem is that at most places the toilet is taped shut.

Tom Hudson
4 years ago

Previous 5ver ,mackensie starwood, had bends in the sewer line. Couldn’t believe they would design something that way. Fought it for 8 years. Have Jayco 5ver now. One of first things I checked before we bought it. Straight drop.

Paul Goldberg
4 years ago

Previous coach, ’04 Southwind, had a 45 deg slant from toilet to black tank. Over 8 years of ownership I had learned: 2 things: 1) how to manage it so it didn’t cause a lot of problem for us. 2) I didn’t want to deal with it ever again. Thus it was something I checked in the Phaeton we bought.

John T
4 years ago

I looked down the toilet of every RV I was interested in at the shows and the dealers, with a pocket flashlight, to make sure the pipe went straight down into the tank. I would not buy an RV that did not.

John T
4 years ago
Reply to  John T

Another thing I looked for was the location of the dump outlet. Many are right at the back of the trailer, where they will get wiped out on a rutted dirt road. I bought a mid-bathroom trailer, with the dump outlet just in front of the wheels. It will never get grounded on any type of bad road.

4 years ago

I Marked the YES column as I have a friend who previously had a Class C with this “bend” in the toilet drain and he forewarned me to always check for this poor design…which I’ve always done so. Currently we have a 2013 Tiffin Phaeton 42LH that the mid bath is situated directly over the black tank and contents drop straight down… never a problem. However, our rear bath has an electronic toilet with a macerator. I know that someday this toilet is going to fail and I’m sure not looking forward to repairing it, but in the past five-six years, it has performed perfectly.

Roger Marble
4 years ago

How about collecting Make, Model & year and if there are actual problems? Would make an interesting summary from actual users. My 2008 Coachmen 2130QB and 2016 Coachmen 23QB both have straight drop from toilet to tank and zero problems. I didn’t notice the change from porcelain to plastic before purchase and doubt that it would have killed the sale but plastic is inferior for a number of minor issues.

4 years ago

I checked no but I probably do look since I’m a curious engineer, I just don’t remember having looked specifically at the plumbing. We have never had problems, but our first six RVs were class Bs with recirculating toilets, then a Georgie Boy and two Newmars which may not have gone straight into the tanks but were arranged so that there were no stoppages. Moving frequently – the motorhome that is – probably helps also..

Guy McWilliams
4 years ago

Had no Problems with our toilet. Then again we have a 2012 Monaco and everything with this motor home is top notch, you get or not what you pay for.

Jim K
4 years ago

Our 07 Winnebago Outlook has a 2″ 45 degree elbow going into the black water tank and I keep a 4′ piece of cut garden hose hidden in the bathroom because every once in a while toilet paper will get stuck there. One of those things I never thought to look at when we bought it. Not a huge deal but I can see where it could get messy for families!

4 years ago

I being a piping tradesman have and do check out rv’s differently and am disgusted with the industry’s ability to manufacture units that do not meet proper plumbing codes.

4 years ago

Our Winnebago Sightseer DOES have a very short elbow before it connects to the tank but only once has it caused an issue….only after excessive amounts of t.p. were used without sufficient water. Otherwise our rv has been very dependable.

4 years ago

I wish I would have checked where the sewer connection is. It is literally 4″ off the ground. As you can imagine, just about anywhere I hook up is an up hill flow. Thank God for sewer solution,

Bob p
4 years ago

We had a ‘99 Bounder 35’ that had a 90 deg. turn toward the rear of the coach that required extra “work” if there was any semi solid waste in the camode. Had to have a plunger handle to break the waste into smaller parts to get it to go down. We ate a high fiber diet to keep waste flushable. That was the first RV I had ever seen that the camode wasn’t directly over the black tank. On our present coach I did check before buying and if we ever get another on I’ll check also.

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