A dedicated washout area should be sized for expected truck traffic, feature impermeable lining

https://fun-wiki.win/index.php/Concrete_Washout_Containment_Options_Compared:_Bags,_Bins,_and_Basins

A dedicated washout area should be sized for expected truck traffic, feature impermeable lining, and provide safe access for vacuum trucks or pumps to remove accumulated liquids and hardened materials.