De or het waterbesparing?

The correct Dutch article is:

de waterbesparing

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

How to use waterbesparing

the waterbesparingde waterbesparing
this waterbesparingdeze waterbesparing
that waterbesparingdie waterbesparing
our waterbesparingonze waterbesparing
your waterbesparingjouw waterbesparing
every waterbesparingelke waterbesparing
which waterbesparing?welke waterbesparing?
a big waterbesparing / the big waterbesparingeen grote waterbesparing, de grote waterbesparing