RV Doctor – Leaking Aqua Magic Toilet

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January 21, 2010

Dear RV Doctor,
The carpet near the back of my Aqua Magic toilet is damp. I cannot see or feel any dripping from the water supply line. Are there internal seals that may be worn or damaged due to use?– Sonny Standridge, (Gretna, LA)


Gary BunzerSonny, indeed, there are many internal seals and gaskets in the Aqua Magic toilet. If the water inlet line is secured properly and not leaking, chances are the water leaks only while flushing the toilet. This is an indication of a leak within the vacuum breaker component located internal to the toilet. It’s easily replaced and Thetford does have replacement parts readily available, typically at any RV parts accessory store. Occasionally the vacuum breaker may be subjected to highly calcified water that may cause a seal or gasket component to leak if a particle becomes lodged inside. There is an outside chance the toilet to flange gasket may be faulty and the toilet leaks as it drains into the holding tank, but your observation that the carpet is damp only at the back of the toilet (directly below the location of the vacuum breaker), is indicative of a faulty vacuum breaker.

(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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  1. Pete Holden

    I had to replace my vacuum breaker a few years ago despite my having winterized the system by running antifreeze through it. I suspected that water managed to hide in it despite the flow of antifreeze. Now the last thing I do before putting my trailer to bed for the winter is to disconnect it from the toilet to allow liquid to run back down the tube and also to allow room for expansion. I must confess ignorance, though, as I don’t really see the point of that part. What would be wrong with a simple supply line connection?

  2. kim

    If water is running down from the vacuum breaker you will be able to see it when flushing. More often when water is on the carpet at the back of the toilet the leek is comming out around the o-ring at the stem of the water valve. The metel stem would chew up the o-ring causing a slow drip. Thetford changed that area with a plastic insert at the o-ring area to correct that problem.


  3. Marika Csatary

    I am looking for a new 5th wheel to place on a piece of Property in Cleveland GA. on the Chatahoochie River. Any recommendations as to the best one on the market for this spot. Any recommendations would be greatly appreciated.

  4. Louella Giddings

    How do you dry out a ceiling that has leaked in a motorhome? A friend of mine had a leak last night during heavy rain here in AZ,it seems to be around the fan area in the shower/lavatory.Their rig has a separate toilet area alone.I’m afraid of mold between roof and ceiling.Can you give me some ideas to pass along?

  5. Boz

    Also check the plastic flush nozzle that is fastened to the back side of the bowl. These have a tendency to crack and leak on the back side of the retaining nut, only when flushed

  6. rick

    no help at all. For some reason, no one can tell me a simple thing like where the bolts are that hold it to the floor.

  7. kim

    I can tell you where the closet bolts are for an Aqua Magic. There is one in front behind the flush pedal you have to hold the pedal down to see it. The other one is in the back on the left side you have to hug your toilet to reach it. If you look at it like a clock the front one is at 5:00 the back one is at 11:00

    ( I work at Thetford in the Quality dept 34 years)

  8. Betty

    my toilet is leaking only in the front-it doesnt leak when water supply off

  9. Margo McClanahan

    I have a Thetford Aqua Magic Fresh Water toilet, when I flush the toilet water
    rushes out the top of the float assembly and leaks onto the floor. What do I need to do to fix this problem?