My Ultimate RV Sewer System Modification

You may remember last year I gave the Waste Master RV Sewer System a full Love Your RV review. I was very impressed with the design and quality of the hose and connections. In the last year, it hasn’t failed to live up to my high expectations.

The only major beef I had with the sewer hose was the permanently attached 90-degree head, storage was an issue. It would not easily slide into the rear bumper like my old hose did. I ended up building a custom carrier for it mounted on top of the bumper. This arrangement worked well enough however I’ve since come to realize there may be a much better solution.

Current bumper sewer hose storage

Soon after my review was published I was contacted by Doug Swarts of He is a long time RVer and the designer of the Waste Master Sewer System. Doug informed me he envisioned the sewer hose to be always hooked to the RV. Therefore it would be unnecessary to decouple it between campsites.  No more dribbling stinky slinky to deal with when breaking camp. The Waste Master hose would live in its own storage box or sleeve.

Waste Master Sewer Storage Solution

I was intrigued and accepted his invitation to drop by the Drain Master shop in Hollister, California for a look at a prototype storage solution he was working on. He explained how the parts would hook up underneath my Cougar fifth wheel and asked if I would like to give the mod a try. Of course, I would!

Building a Better RV Sewer System

The Plan

The plan was to mount an LCI (Lippert Components Inc.) plastic storage box about where the existing sewer output point was on my 2011 Keystone Cougar trailer. The LCI box is uniquely sized to store the Waste Master Sewer Hose with just one 180 degrees coil required. A hole would be cut in the side of the plastic box and the sewer hose would be connected to the RV’s main sewer output via its cam lock connector.

LCI storage box with prototype mounting brackets

To secure the storage box I would use a set of prototype metal brackets supplied by Drain Master designed to bolt onto the trailers steel I-Beam frame rail. I wanted the box located as close to the rear wheels as possible for best ground clearance but not under our slide out room. So, I picked my mounting location as close to the slide out as practical.

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A Hitch in the Plan

Everything seemed really easy until I took a gander under the Cougar. I instantly remembered the second drain pipe teeing into the main sewer drain from our RV galley tank. It’s located to the rear of the trailer meaning it would have to cross over the new storage box. I wanted the box sitting up snug to the Cougars belly for maximum ground clearance so routing the pipe over was a no go. Especially, if I wanted to maintain a downward drainage angle.

Galley Drain Pipe

I decided to reroute the 1 1/2 inch galley drain pipe around the back of the box. This, of course, created another issue. It would make removing the coroplast underbelly covering a complete pain since the other side is covered with the propane piping. Given my history of upgrades/mods and for future repairs I knew easy access to the guts of the beast is a must.

The solution I came up with was to use a piece of heavy duty flexible marine drain pipe used for large boat bilges. Each end would be held in place by a hose clamp allowing for quick removal and reinstallation.

Flexible Drain Hose

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Let the RV Sewer System Mod Begin

The first thing I did was unscrew and cut a large section of the coroplast board underbelly out. I wanted plenty of room to work with. It would be re-screwed in place after the work was done and any seams sealed with 2.88″ wide Gorilla tape.

If you saw my blog post detailing my HepvO valve install you know plumbing is not my forte but I was still game, out came the hacksaw. I cut the main drain back enough to add on a new tee section and the Waste Master female cam lock. Then I crawled under the rig and cut off the galley drain a foot or so before it disappears into the underbelly.

Cut out plumbing section

I then whipped out the ABS cement and joined the new T section and female cam lock onto the main drain output. Then I cemented on two 1 1/2” couplers allowing me to screw in another pair of couplers which in turn let me attach the flexible drain hose with hose clamps. What a mouth full. I was starting to become good buddies with the Home Depot plumbing guy. 😉

New plumbing couplers and tee section

Gluing the plumbing parts

Next, I mounted the box by bolting it to the trailers I-beam frame rail. To secure it in place, even more, I ran a piece of plumber strap from an internal horizontal frame rail to the boxes rear support bracket. To the same rail, I added a hanger for the flex hose as it made its way behind the box. I then secured another hanger on another frame rail nearer to the galley tank output. Finally, I attached both ends of the flexible hose using hose clamps.

Galley drain hose and hangers

Looking at the mounted storage box under the rig

Added a Check Valve the Wrong Way

When the Waste Master hose is pulled out and extended suction is created. A check valve needs to be added to allow air into the system. I drilled out a hole in the ABS pipe then threaded/glued the special check valve in place. (Thanks to Doug at Drain Master for kindly providing me one)

The check valve should be installed vertically above the pipe for best operation. I messed up and forgot to install it before the pipe was glued on. Doh! Leaving myself insufficient space to drill the hole. I had to install the check valve on an angle.

Check Valve Installed

Another Problem to Solve

I ran into another snag when I went to line up the newly attached female cam lock to the male end of the Waster Master hose. The design Doug showed me had the hose entering the box perpendicularly. This allows the rugged plastic collar of the hose end to be against the plastic edges of the entrance hole and the cam lock levers to function properly. Unfortunately, since I had previously cemented the female cam lock close to an ABS elbow I was going to be entering the box at an angle.

So, instead of the plastic collar against the thin plastic edge a section of the inner membrane would be. As to not damage this membrane, I added a sponge gasket for protection. It’s actually a sponge toilet bowl gasket! I took a utility knife and cut a groove around it and placed it the boxes hole as a makeshift grommet. It turned out to be a great idea I think. 🙂

Hose enters the box at an angle

It’s always fun trying to custom build something, isn’t it? But at least others get to learn from my mistakes. As soon as I can get hold of a new female cam lock connection I’ll correct these errors by redoing the plumbing between the rigs main sewer output and the hose storage box.

Video Detailing the RV Sewer System Mod

Very Happy With the New Sewer System

I have to say this mod is a great success. Why the heck don’t RVs come this way? Now when it’s time to dump the waste tanks it’s a breeze. Even my squeamish wife Anne will want to partake in the dumping duties. Well, maybe not, haha. But at least if I’m away and she *really* has to do the deed it won’t be such a nasty task.

Now, we just open up the new sewer hose storage box. Pull out the Waste Master nozzle and stick it in the sewer hole. Then flip open the valves and let her rip. Once the job is done, close the valves and place the hose back in its box. No muss no fuss.

It’s so much more sanitary compared to what we have traditionally been offered by the RV manufacturers. It’s about time we RVers demand they improve this part of RVing.

Modifying the RVs sewer output plumbing and adding a hose storage box for my Waste Master sewer system - #RVing #RVmod

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  • Richard Cross

    Ray, what a great setup! A very clear, well-done video explaining your new setup.
    Couple of questions along the likes of your “next time” thoughts…
    1) If you were going to go into the box straight in, could/would you have cut your hole in the next pre-formed arch back in the box? You used the first arch in keeping with your need to approach it from an angle. Just wondered if any of those preformed arches are available for cutting an entrance hole. Would using the second or third arch back pose any difficulties in the way the hose stores in the box do you think? If you were going to cut a second hole and move the entrance back, could the piece you cut out be patched back into the first hole do you think?
    2) In hind-sight, was there enough room above the box to slide the kitchen gray 1-1/2 inch line through? Or do you still feel it’s best to route it around with the U to keep a downward grade?
    You did a great job on this mod. My questions are because I don’t have your experience with some of these things and would like your input about how critical some of these possible alterations might be.
    Thanks again for all your great videos. You’re the mentor I’ve never met 🙂
    Richard C.

    • Thanks Richard, could do but I think if I place the hole further back it will give less room for the hose so the nozzle end would have to be stuffed in. It sort of stores in a U shape right now. nice to have the nozzle right at the door end. Also where it sits now I don’t have to crawl under the trailer if I need to disconnect. Like if I want to add in my extension hose for longer runs to the sewer hole.
      If I went over the box with the 1 1/2 there definitely would have been a slight upslope to it so some drain water would be trapped.
      My problem was I’m not sure how much clearance the box will need off the ground until I get out there traveling again so wanted to err on the side of caution.
      A bigger rig may have a lot more ground clearance and it may not be an issue.
      Cheers Ray

      • Richard Cross

        Thanks Ray. I figured where you entered the box could impact on how, and how easily, the hose would go back in. Good to know in advance that entering as far forward gives you better clearance to loop the hose in easily when storing. Hard to tell before you cut an opening and try stuffing it in. I’m definitely bookmarking this mod for the future. Thanks again.

  • Gordon Cindy

    Ray, as Roy said I’d like to do as you did and connect my kitchen drain to the main drain. Did you happen to make a video on how you did that?

    • My trailer came already plumbed that way. 🙂

      • Gordon Cindy

        Oh; interesting. Then I’ll ask you a question about how it’s configured… are there two gate valves at the galley tank end?I see there are no valves at the 3″ discharge end up front. In other words, can you close off the 1 1/2″ pipe going forward and dump from the rear 3″ connection? I’m trying to get an idea how the connection from the galley tank is set up. Hope this makes sense.
        BTW, Happy August!! Did you say ‘rabbits’ today? 🙂

        • There are three waste valves, one for each tank. They are situated right near the output pipe of each tank. Up in the underbelly. This is helpful to prevent freeze ups but makes them a little difficult to work on. I did a post a few years ago that may help you – Has a video showing inside underbelly and a crude hand drawn diagram of the tank layout. Cheers Ray

        • Gordon Cindy

          Thanks Ray, your little tour was very interesting. I see that you don’t have a drain for the galley tank except for the 1 1/2″ pipe that goes to the drain for the other tanks. Our trailer, of course, has one drain for the Black and Gray tanks and then another drain for the Galley tank. I’d like to connect the Galley drain to the other one. I guess I’d have to install a valve between the Galley tank and any pipe I installed to the other drain point. Then there would be two valves, the original and one I install. I’ll have to take a close look, as you did, inside the belly cover to see how I could install the valve and how to run the pipe.
          Thanks again!

  • SayItsNotSo

    Ray, these videos are great! I watch them whenever I can.
    Last RV trip I ripped off my Valterra waste valve blade when I stopped for fuel (OH NO!). Been researching options to fix the problem…..

    Seeing what you’re done in this modification makes me think I can repair it in the next few days before I return the RV to storage. Then it will be ready for the next trip. Good stuff!

    • Awesome. Thanks!

  • Roy

    Your sewer box is a possible next step, but you encouraged me to reroute my kitchen gray to join the bath gray and black. That will cut me down to one stinky slinky vice two.

  • Kevin

    Oh my Goodness, You’ve come up with the ultimate Rube Goldburg Machine of RV Sewer systems- No thanks, I keep my workable system!!!!!!!!!!!!!!!!

    • Thanks for the feedback. Happy camping!!!!!!!!!!!!!!!!