RV Doctor – How Do I Install a New Toilet in My RV?

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September 18, 2009

Dear RV Doc,
How would I install a new toilet in my RV? I’d like to go to a bigger one. Is the RV toilet the same as a toilet in a home with the two bolts and the wax ring? Or is it an entirely different hook up? – Armin Meyer, (Tacoma, WA)


Gary BunzerArmin, the RV toilet differs from a typical house toilet in that it does not have a back tank. As you know, coach owners must conserve all resources so RV toilets are designed without a back tank in order to conserve water. They flush using very little water comparably.

The good news is that they all mount to the floor flange in the same manner with a couple of exceptions. Some RV toilets utilize four mounting bolts instead of the usually two. And some two-bolt installations have the bolts positioned at 11 and 5 o’clock instead of 9 and 3 o’clock. Adapter kits, however, are available that make RV toilet installations simple for most handypersons.

There are many RV toilets on the market; take a look at any Camping World store for an assortment of sizes and styles. I personally favor those made from porcelain instead of the usual plastic. They have the look and feel of a standard house toilet, sans the back tank. As a suggestion, check out the Magnum Opus RV toilet, developed by Dometic. It is constructed of 100% vitreous china.

RV floor flanges are identical to most modern homes but rather than a wax ring, I recommend a rubber seal to eliminate the possibility of heat softening and distorting the wax ring, thereby, loosening the toilet. This situation isn’t common with houses, but could be with motorhomes.

(Please feel free to comment, however, please also note that due to the volume of communications I receive from multiple channels I cannot guarantee a personal response in every instance. However, questions of an overall general interest may be considered and published in an upcoming RV Doctor column.)

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  2. pat

    Does anyone know if and where there is a catch pin or cross piece where the bowl contents hit on the way down and break apart (Thetford IV). Thank you. P.S. My Norcord just quit working on Electric, I’ve read this one other threads on other site but it’s all indecipherable. The “x” check light comes on and it switches to gas. I’ve yet to check the outlet for the refrigerator, I’m thinking Inverter problem, but it seems like a common occurrence. Please tell me it’s a fuse somewhere and I don’t have to take this thing out and stand it on its head lol. Thank you again.

  3. Jack

    How do I replace a seat & cover assembly on my Aqua Magic IV commode

  4. kim

    Thetford also offers a wide range of china toilets, most of them mount on the floor flange at the 3 and 9 oclock possitions.