PDFWAC 16-201-070
Secondary containment of liquid bulk fertilizers—Precipitation accumulations.
Precipitation may not be allowed to accumulate in secondary containment to the point where it:
(1) Reduces the capacity of the secondary containment below one hundred ten percent of the volume of the largest storage container within the area plus the displacement of all other storage containers, appurtenances, and other items within the containment area;
(2) Increases corrosion of storage containers or appurtenances; or
(3) Impairs the stability of storage containers.