I'm trying to help my relative drain a waterbed. It's old (maybe 20 years) and they don't know the brand, nor do they have or remember any attachments or adapters that may have come with it.

Most descriptions I've read online for how to do this simply say "attach your hose to the bed's drain valve" but this one seems to have a non-standard valve. It's too large for a 3/4" garden hose connector. It seems like a 1" connection but the threads seem too sparse and I haven't yet found anything that looks like it would work for attaching the hose.

Furthermore there's also a sort of button inside the valve that seems to allow air out when depressed. I suspect the valve is sealed when it's not pressed.

The bed doesn't have to be usable again after it's drained as we're planning to dispose of it. Should we cut off the valve?

the valve with threads button in center on spring valve with measurement

  • 1
    The problem with "cut off the valve" is making sure you don't end up with the bed self-draining all over the room while you are trying to sort out how to do it with a hose and still have nothing for the hose to connect to - so plan well and throughly. Showing all of the text printed around it might help someone identify it.
    – Ecnerwal
    Apr 3, 2022 at 3:10
  • With a drain kit (see my answer) and a long hose, you can develop a siphon that will suck the whole bladder empty. If you cut it out, it’ll be more cumbersome to suck it all up.
    – Tim B
    Apr 3, 2022 at 10:30

2 Answers 2


That white valve inside the pop up fitting comes out. Once it does, there is a fitting from a “waterbed fill/drain kit” that is friction fit into the hole.

Searching online showed many hits, so I won’t link a specific one. But in this example, the blue piece on the right is the one that is pushed into the mattress. It fits a male garden hose connector.

The blue piece on the left connects to a faucet, and uses Bernoulli principle to supply vacuum to the hose. If it’s not lower than the mattress, you would need to run the faucet the whole time. Once the hose is full, it will sustain a siphon as long as the drawing end is lower that the mattress.

waterbed drain/fill kit

  • 1
    Thank you -- I can't confirm until I get over there again, but I assume for now that pulling out the white valve will do the trick :)
    – woolcap15
    Apr 3, 2022 at 16:54

Cut off the end of a garden hose and stick it in the fill valve. You'll have to hold the hose end on the bottom of the mattress. Then attach your drill to a drill pump.

enter image description here

BTY: That white plastic cap/plug pops out of the fill valve.

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