Thursday, October 6, 2022


Ask Dave: My gray water tank valve won’t open. Why not?

Answers to questions about RV Repair and Maintenance from RV expert Dave Solberg, author of the “RV Handbook” and the managing editor of the RV Repair Club. This column appears Monday through Saturday in the RV Travel and RV Daily Tips newsletters. (Sign up for an email reminder for each new issue if you do not already receive one.) Today Dave discusses a gray water tank valve.

Gray water tank valve not working

Dear Dave,
I can’t get my gray water tank to drain on my Winnebago Era 2020. The black water will drain, so I know the macerator pump is working. I took a video of the valve. It starts with the handle being in the open position. It seems like that big first black block should move but I’m not familiar with it. Thanks for the article. Hopefully, I’ll be able to winterize. I just bought the vehicle used and discovered this problem. —Ron

Dear Ron,
I took a screen capture of the video you sent and posted it above. It looks to be a basic Valterra spade valve for the gray water tank, as it has 1.5” pipes going to and from. The black block should not move as the handle/cable is connected to a spade valve that moves back and forth inside the sealed housing.

Here is a sample of one that I use for demonstrations in the Q&A and Gold events:

Your valve has a longer handle and probably even a cable that goes to the other side of the rig, but it functions the same. Pull the handle and the stem moves out, pulling the spade and opening the valve to allow water/sewage out. This one happens to be a Camco version that I got at a local Walmart in the RV section.

Possible causes to check

I believe your stem disconnected from the spade and they are not screwed or threaded as the handle spins freely. I would believe it has some type of groove and ring clamp. You will need to take the bolts out and remove the mechanism. Since it’s gray water, it will not be as messy.

I would place a funnel or trough under the valve and a large pan on the ground. I have used an old plastic sled in the past. Dump the water out and you should be able to remove the valve. You might have to take the handle off at the harness on the other side and remove the entire mechanism. Then you should be able to take it apart and see if it can be fixed or if it needs to be replaced.

Read more from Dave here

Dave Solberg worked at Winnebago for 15 years developing the dealer training program, as marketing manager, and conducting shows. As the owner of Passport Media Creations, Dave has developed several RV dealer training programs, the RV Safety Training program for The Recreation Vehicle Safety and Education Foundation, and the accredited RV Driving Safety program being conducted at rallies and shows around the country. Dave is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.


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11 months ago

Try spraying the valve with wd40. Sometimes it sticks from setting long periods of time and the valve won’t open

11 months ago

Just replace the valve. They do fail and are cheap. Nice not to fight a sticking valve. Be glad it’s the grey water valve. Just what I would do, and have done.

11 months ago
Reply to  tom

Agree. If you are that far along you might as well replace. If the old one broke once it will break again.