Modular power washer system, method, control circuit and kit therefor

A modular power washer contains a power washing system (10), containing a base unit (20) and an accessory unit (34), wherein the accessory unit (34) is removably-attached to the base unit (20). The base unit (20), contains a housing (22), a pump (26), a motor (24), a power source (28), an input valve (64), and an output valve (32). The housing (22), contains the pump (26), and the motor (24), therein, and the housing (22), at least partially contains the power source (28), therein. The motor ( 24), is operatively-connected to the power source (28). The pump (26), is operatively-connected to the motor (24). The pump (26), is fluidly-connected to the input valve (64), and the output valve (32). The accessory unit (34), is selected from a hose storage unit (68), an additive tank (88), a handle (36) a roll bar (50), a frame (72), a wheel (74), and a combination thereof. A kit and a method of use are also described herein. A control circuit is also described herein.