Washing down : Water descending from above

Hi,

I am looking for some commonsense wording for a “rule” with regard to owners at higher elevations washing down their glass balustrades, and allowing the water to descend on the units below, particularly the units at ground floor level.   The ground floor units can sometimes have their peaceful sunshine ambiance destroyed by a deluge.   However, not all upper floor owners can wash down during a thunderstorm.