De or het vochtwering?

The correct Dutch article is:

de vochtwering

Rule Words ending in -ing: almost always de. See the rule

How to use vochtwering

the vochtweringde vochtwering
this vochtweringdeze vochtwering
that vochtweringdie vochtwering
our vochtweringonze vochtwering
your vochtweringjouw vochtwering
every vochtweringelke vochtwering
which vochtwering?welke vochtwering?
a big vochtwering / the big vochtweringeen grote vochtwering, de grote vochtwering