Happy D adjustment

Is it possible to adjust the amount of water flushing in a Duravit happy d toilet?

If you are trying to increase the amount of water in a flush, the answer is no. You can not defeat the 1.6 gallon maximum.

WEll, that's not always the case! Very few, if any, of the current toilets empty the entire tank when you flush. If you hold the handle down on most, you can empty the tank. Now, that may be just a waste of water...depends on the toilet. Also, if you replace the flapper and don't use an exact replacement, it might stay open longer as if you had held the handle. But, you should not do this...it defeats the whole issue about mandating saving water and sewer use.