A drilling fluid control system (100) has subsystem modules (102A-102H), an output (104) and an input (106) connected with interconnecting conduit (110). Each subsystem module (102A-102H) has a function. The subsystem modules (102A-102H) may be an active mud pit module (102A), a mud mixing module (102B), a chemical storage module (102C), a rig pump module (102D), a back pressure control module (102E), a primary shaker module (102F), a secondary shaker module (102G) and/or a shaker pit module (102H). The subsystem modules (102A-102H) with the same function may be interchanged without changing the input (102), the output (102) and the interconnecting conduit (110) of the drilling fluid control system (100). Additionally, the sub-system modules (102A-102H) are configured to fit within intermodal shipping containers.