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How To Fix An RV Toilet Leaking At The Base

Is your RV toilet leaking at the base? An RV toilet leaking at the base is a common problem and thankfully a fairly easy repair.

“The most likely issue is a bad flange seal, which is located underneath the toilet. To check the seal, you’ll need to disconnect and remove the toilet (don’t worry — it’s easier than it sounds).” Per RV Bloggers Angela & Graham

What To Do If Your RV Toilet Is Leaking At The Base

Remove the RV toilet

Start by removing the toilet to determine if the problem is with the seal or floor flange itself.

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To remove the toilet:

  1. Dump and rinse the black tank. Click here for tips on how to avoid unpleasant odors when you remove the toilet from the floor flange.
  2. Prepare a spot to set the toilet once it is removed. If in the RV, consider using some cardboard and/or some old towels to set it on to protect surfaces in the RV.
  3. Turn off the city water and/or the water pump. Flush the toilet to release any remaining water pressure in the water line feeding the toilet.
  4. Remove the freshwater line from the back of the toilet. A small mirror can prove useful in this step.
  5. Remove the two bolts at the base of the toilet. Lift the toilet straight up off the flange bolts and set it down in the prepared location.

Note: Be careful to not accidentally drop anything into the black tank while the toilet is removed.

Now you will need to inspect the gasket and floor flange to determine where the leak is occurring. Typically, there will be tell-tale signs of leakage to let you know.

Carefully inspect the floor flange

Problems to look for on the floor flange include cracks, warpage, or if it was not properly secured to the floor or screwed/glued tightly to the pipe below it. If you find any of these problems, repair as needed or take it to an RV repair facility.

If the flange looks okay, the problem most likely is with the gasket. Even if the problem is with the floor flange, you will always want to replace the gasket anytime you remove the toilet from the flange. RV toilets typically use a foam gasket, rather than a wax ring like residential toilets, so be certain to get the right type for your RV toilet. Gaskets can be ordered from Amazon or picked up at your local RV dealer. Mount the new gasket on the base of the toilet, not the floor flange.

Reinstall your RV toilet

  1. To avoid tearing the new gasket on the toilet, align the mounting holes on the toilet over the T-bolts and slowly lower the toilet over the bolts.
  2. Use the nuts to resecure the toilet to the floor flange. Be careful to not overtighten the nuts, which could damage the toilet. Sit on the toilet to make sure everything is secure and that it doesn’t wobble. Tighten more if needed.
  3. Reconnect the freshwater line to the toilet; be careful to not cross thread or overtighten the fitting. 
  4. Turn the water back on, flush the toilet, and check for leaks.
RV toilet leaking - Cracked Flange
A cracked flange can be the source of the leak – Photo iRV2

This should put an end to your RV toilet leaking at the base.

Make sure you keep track of all your RV maintenance and repairs with an online tool such as RV LIFE Maintenance from RV LIFE. Not only can you keep all of your documents in one place, but you’ll also receive timely reminders when maintenance is due to help you avoid costly repairs and potentially serious accidents.

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