Thursday, September 21, 2023


Easy step-by-step DIY RV toilet seal replacement

By Cheri Sicard
Brian, from RV with Tito DIY, one of our reader’s favorite RV repair how-to YouTubers, has produced a handy video that most RVers are going to need at some point. That’s because after a while your RV toilet seal is bound to wear out. I know I am at that point; how about you?

If your RV’s toilet won’t hold water and you can hear a steady drip and water is in the bowl, your RV toilet seal might also need replacing.

According to Brian, this is an easy maintenance task that you can accomplish for about $15, and he is going to show you, step-by-step how to do it.

What’s involved in the RV toilet seal replacement job?

#1 Determine what kind of toilet you have. Most likely it’s Thetford or Dometic. If you have the original documentation that came with it, so much the better. This will help you find the proper replacement seal and what sockets you will need to remove the bowl. The replacement seal kit comes with two seals, one for the base and one for the bowl.

#2 Turn the pump off because it is time to disconnect the water lines from the toilet. Brian shows you how in the video.

#3 Remove the bolts and take the toilet up and off. This will vary a little from toilet to toilet.

#4 Remove the bowl from the toilet. Once you do, you can easily see the seal that needs to be replaced.

#5 Replace the bottom seals. Clean the area first before popping in the new bottom seal. Brian recommends you give the new seal a coating of the plumber’s grease or even some Vaseline. Same with the seal for the bowl.

#6 Replace the toilet bowl. Brian shows how it simply goes back together in the video. Be cautious not to over-tighten the bolts or you run the risk of cracking the toilet.

#7 Reattach the toilet to the RV. Going in reverse, put back the bolts you removed in Step #3.

#8 Reattach the water lines. Clean the area, double-check everything, and now you are ready to test your new RV toilet seal.



  1. While the water is off, add a shut off to your toilet. If you have PEX lines and use a press on fitting, the only tool needed is a sharp utility knife and the skill to make straight smooth cuts (or buy an inexpensive plastic pipe cutter).
    If your toilet valve leaks, you can shut it off and still have water elsewhere.It is easier to use a cleaning wand without water also cascading into the bowl.If your level sensors are wonky, you can use a flashlight to visually see the tank level.

  2. I stay away from any type of petroleum products on rubber seals as it will break down the rubber. Instead I use a O-ring grease that you can get in the plumbing aisle of the big box or hardware stores. Once a month I put on rubber gloves, turn off the water, open the flush gate, clean the seal and apply the O-ring grease. Also do the same before storing the rig.

    • I can hear mine and my biz partner always tells me I need hearing aids. LOL. I really need to replace the seal.

  3. On Dometic Series 300 models, you can change the flush valve seal without removing the toilet. Check it out on YouTube.

  4. WOW, how easy was that ! Thank You so much,,, Haven’t had to do it yet, but, will do it myself when the time comes….


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