Newbie Waste Valve Question

No way I would consider that normal.

No. Some seepage up to a point but I would consider a cup is excessive. Especially new.
Could try running clear water down drain working the valve, but dont jam it home. Either valve gasket not sealing or debris in sealing area keeping it from fully seating.

How long between dumps.........how long to accumulate this 'cup' of liquids???

Could be seepage
Could just be residue from dumping and then capping line off vs letting it drain/dry after closing dump valve

I'd try opening and closing firmly a few times each time you dump and see if it fixes the issue.

It could be perfectly normal if there is plumbing between the valves and cap that hasn't fully drained (usually due to the angle of the truck during dumping). Not every camper has a straight shot from valve to the outlet.

Possibly typical, but not proper behavior.

Our valves would leak a teaspoon of waste between dumping. Not a big problem. I replaced them because I have experienced about ten gallons coming out when the cover was removed, and KNOW I wanted to avoid that again.

Valves are not very expensive. Amazon sells just the seals.

Matt B

It can depend on where the black tank is located - if the tank is located forward (such as some Lance models) and a drain pipe running toward the back - then liquid can remain in the length of drain pipe after the valve is closed.

Make sure the camper is tilted toward the sewer receptacle when draining AND wait a few minutes AFTER closing the drain valve. This will allow any remaining liquid in the drain pipe to drain out and not accumulate at the cap.

I have not had it happen with new valves. As the age, or get a little "stuff" in the valve slide it is very common. Due to this, I only use end caps that have a good handle and a small hose cap with a ball valve. I open the ball valve first so I get no surprise.

Valterra F02-3106BK Black Bulk EZ Coupler Valve Cap with Handle

Orbit Plastic Garden Hose Faucet Shut-off Coupling

Wayne

I have had that issue through the years but corrected it by replacing the valve. Have the dealer replace the valve they are cheap.

I don't like to have to deal with that type problem, so I installed an elbow and a twist on waste valve on the outside. If the primary valve starts leaking I find out without getting splashed when I remove the outside cap. I think it was $16 on ebay a couple years ago.

A bit of vaseline applied to the blade and the slot it moves in will solve it if you can get your hand up in there...