How To Replace Your RV Toilet Ball Valve Gasket

At first glance, RV toilets look similar to household toilets. But there are some major differences between them that will require extra maintenance for your RV toilet. Most notably, household toilets should always have water in the toilet bowl whereas RV toilets need to be able to have no water in the toilet bowl while the RV is moving. An RV toilet ball seal allows for this. On the other hand, when the RV is parked at a campground or campsite, there should always be water in the toilet bowl.

This is your front line of defense in keeping odors from entering the RV through the toilet. Again, the RV toilet ball seal comes to the rescue, allowing water to remain in the toilet bowl without draining into the black water holding tank.

The toilet ball seal also has the ability to keep odors from creeping into the RV even without water in the toilet bowl by making a semi-air tight seal. But as you can imagine, this gasket can become worn or damaged over time and with usage. When this damage does occur there will no longer be a watertight seal, causing water to leak into the black water holding tank. Fortunately, the gasket can be replaced with relative ease.

To begin, you will need a pair of disposable rubber gloves. It will make the task of replacing the gasket much more pleasant if the black water holding tank is empty as well. Part of the process of replacing the ball valve seal includes keeping the ball valve in the open position so you can access the gasket.

Because of this, you will need to have the water pump turned off and the RV disconnected from any city water sources. This will allow you to replace the seal without having water flowing into the toilet the entire time you are working on the toilet. 

Removing the old gasket is very simple. Make sure the ball valve is in the open position by holding the toilet flush pedal down with one hand or by opening the valve and taping the pedal to the floor with duct tape. With your gloves on, remove the gasket by pinching it between your fingers and gently pulling down towards the black water holding tank.

Work your way around the gasket with your fingers until the gasket pulls free from the toilet. Be sure not to drop the gasket down the pipe! If the gasket does fall into the tank or down the pipe it can be very difficult to retrieve and may cause clogs or other problems in the black tank. 

Once you have successfully removed the gasket from the toilet, clean the surfaces of the toilet that the seal comes in contact with.

I typically use toilet paper to wipe down these surfaces, because if toilet paper were to drop into the pipe or the black tank beyond, you don’t have to worry about retrieving it or having it fail to break down in the black tank. It is best to avoid using paper towels or wet wipes, as these would be a concern if you dropped them into the toilet. Once the surfaces that make contact with the gasket are clean you can install the new gasket.

In order to avoid dropping the new gasket into the black tank, I place the gasket midway up my hand as though I was putting on a bracelet. This allows you to use your fingers to work the gasket into place in the toilet while stabilizing the gasket with your palm so it doesn’t fall into the pipe. The gasket has a recessed area between the upper and lower rubber flanges. This area mates with a plastic lip that is just above where the toilet flush ball valve opens and closes. The ball valve is in contact with the gasket all of the time until the toilet flush pedal is pressed to the floor of the RV. When the flush pedal is pressed the ball valve rubs against the gasket until open and any water, waste and toilet paper is allowed to flow past the gasket and ball valve into the pipe that connects the toilet to the black water holding tank. You will need to make sure that gasket is fully seated on the plastic lip all of the way around the toilet hole.

I like to start by getting one section of the gasket in the correct position and with my other hand gently work the gasket around the hole. It usually takes a few tries in order to get the gasket to seat properly. When the gasket is properly installed in the toilet, there should be no deformed areas on the top, bottom or sides of the gasket as it sits in the toilet.

The ball valve should also be able to move relatively freely across the lower surface of the gasket without getting stuck. If you have found the ball valve getting stuck or see any deformed area around the gasket you will need to continue working the gasket around until it has seated completely. Once you have fully seated the gasket in the toilet and the ball valve is able to move open and closed without getting stuck, restore water pressure to the toilet. 

Fill the toilet bowl half full with water and keep an eye on it to make sure that the water level does not drop.

If the seal is holding water then you have successfully replaced the toilet seal, well done! If water is slowly or rapidly draining out of the toilet while you are watching it, then the gasket may need to be reseated. Follow the instructions above again and best of luck to you!

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