Mixer tap with push up waste

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I'm curious about how you're meant to stop water seeping down past the push rod and pooling on the floor.
I've had mine dismantled and the rod does not have any o rings fitted and certainly no groove to accommodate an o ring.

 

[oldbuffer]

1. The only water that is going down there is the odd splash from using the taps.
2. The rod is a reasonably tight fit in the body of the tap, so will minimise what goes down.
3. Most I've seen have an O ring, but it's loose, not fitted in a groove.
4. Is suspect the tiny amount of water involved evaporates before causing a problem.