PDFWAC 246-215-05320
Design and construction—Tank vent, protected (FDA Food Code 5-302.14).
If provided, a water tank vent must terminate in a downward direction and must be covered with:
(1) 16 mesh to one inch (16 mesh to 25.4 mm) screen or equivalent when the vent is in a protected area; or
(2) A protective filter when the vent is in an area that is not protected from windblown dirt and debris.