I actually agree on the hosing of your car thing. I won't bore you with the scientific details though
If they care so much about water not going into the gutter though, they should encourage rain gardens.
Btw, nandina has some medicinal uses.. you should look into it.
I've working on an edible/medicinal/useful garden. Slowly replacing my gosh darnoodley pittosporums with blueberries!