Usable open space. For all permanent residential uses involving three
or more housing units there shall be provided a usable open space
area equal to the lessor of 500 square feet per housing unit or 10%
of the gross lot area. The usable open space shall have no dimension
less than 20 feet. The required open space shall be exclusive of driveways,
drainage swales or other drainage facilities, parking lots or storage
areas. The following additional regulations shall apply in determining
the required usable open space:
(a)
Swimming pools, gardens, patios and paved recreation areas may
be developed in the required usable open space.
(b)
An accessory building may not occupy any part of the required
open space.
(c)
The slope of any usable open space shall not exceed 10%. The
open space may be provided on a deck or balcony.