Replace RV Sewer Valve | 8 Easy Steps

How to replace 3 inch sewer valve

Are you finding it difficult to open and close your fresh or black water valves?

When you remove the cover from your sewer system does it leak water?

If so, it might be time for you to replace them.

These are the two main reasons why you may consider having to replace the valve. Replacing the sewer valve is a relatively easy task and can be accomplished within about an hour.

Sewer valve leaks

It is quite common for a valve to leak if you have some debris that has been lodged between the blade and the rubber gasket.

If this is the case, try opening and closing the valve several times and see if that resolves the issue.

If you continue to find liquid when you remove the drain cap then it is time to replace the leaking valve.

Prices pulled from the Amazon Product Advertising API on:

For a quick fix you could try applying light grease to the metal handle shaft or spraying with a lubricant and moving the handle in and out. if this doesn’t help then I’d recommend you replace the valve before it gets stuck closed and you have a full tank which makes it impossible to replace.

Don’t wait until it’s stuck

If you’re experiencing either the leaky valve or sticking valve head over to your local RV store and pick up the replacement valve. you don’t want to be the guy with the valve stuck closed and a full tank. this turns and easy 1 hour job into a very disgusting task.

RV waste valve sizing

The typical freshwater valve is 1 1/2 inches in diameter.  Your black water valve will be 3 inches in diameter. Valterra sells an aftermarket valve for both your fresh and black water. They are relatively cheap and come with all the hardware required for the average DYI person.

The only recommendation that I would make is to replace the standard bolts that are provided with the kit with stainless steel ones that you can purchase from your local hardware store. The reason I switch to stainless steel bolts is because they don’t rust and when I have to replace the valve again in the future, I won’t have to use a hacksaw to remove them.

Tools Required to Replace Waste Valve

The 3″ Valterra replacement kit come with everything that’s needed to replace the valve.  You will need a wrench to remove the bolts and possibly a hacksaw if the original bolts are rusted.

When I went to go replace mine after about 5 years of use, they were totally rusted and I needed to use the hacksaw to cut them off and that’s when I made the decision to use stainless steel bolts.

Another thing to consider when you are installing the valve you may want to use some grease on the blade and the rubber seals to ensure that they don’t seize sooner than necessary.


  • Sewer Valve Replacement Kit
  • Two wrenches
  • Light grease for lubrication

Removing the Valve

  1. Empty and thoroughly flush the black tank. Drain the gray tank to flush away any remaining black material. Close the valve.
  2. Place a container underneath the valve to catch drips. Suitable containers include an old coffee can or aluminum baking tray.
  3. The valve slides in between two flanges. It is held on with four nuts, bolts and washers. Hold the bolt still with one wrench and turn the nut until all are removed–or vice-versa.
  4. Gently pry apart the two flanges and work the valve out. If there is resistance, push on the sewer pipes so that they move away from one another. The valve may drop out, or you may need to twist it gently.
  5. The valve has two rubber gaskets, one for each flange. Check to see that they came out with the valve. If not, pull them off the valve. There may be some dripping at this stage.

Replacing the Valve

  1. Gently slide the new valve between the flanges. Using stainless steel bolts start the bolts and turn the valve gently to ensure it is seated firmly.
  2. Gently tighten, but do not overtighten, the bolts and nuts. Use the stainless steel bolts that you purchased at your local hardware store. They are 1/4″x20 at 2″ in length. This will ensure the next time you have to replace the valve it will go much easier. Mine were totally rusted after only 5 years of use.
  3. Wipe off any remaining mess and discard the rags. Your new valve is ready to use.


Use stainless steel bolts that can be purchased from your local hardware store for under $2. This will ensure an easy replacement the next time you have to replace the valve.



Preventing a sticky valve is much easier than having to go and replace the valve every three to five years. Applying a small amount of light grease or some silicone spray on the pull handle shaft should be done once or twice a year at the minimum. as there is no way to access the blade without removing the valve there’s not much else you can do.

What can I do if my valve is stuck open in an emergency?

In an emergency, Valterra has a Twist on waste valve that that connects to the end of your sewer outlet just like the normal 3 inch sewer hose does. You should be able to get this at your local Walmart or RV parts store.

How to open a stuck closed valve

If your tanks are full and your valve is stuck closed there’s only a couple things that you can do. You can try spraying with penetrating oil and letting it sit for a while and see if that helps. The other option is to use a set of vice-grips to get better leverage while trying to open the valve.

Recent Posts