A mobile water purification system having a trailer, a pretreatment subsystem having a cyclonic separator, a filtering subsystem fluidly connected with the pretreatment subsystem, the filtering subsystem having at least one bedded filter; a reverse osmosis subsystem fluidly connected with the filtering subsystem, the reverse osmosis subsystem having a waste output and a product output; a collection tank fluidly connected with and downstream of the reverse osmosis subsystem; a distribution subsystem fluidly connected with and downstream of the collection tank; a source water inlet mounted to the exterior and fluidly connected to the pretreatment inlet, the source water inlet outside of the at-least partially enclosed space; and a discharge water outlet mounted to the plurality of sidewalls and fluidly connected to the pressure tank, the discharge water outlet having an outlet opening outside of the at least partially-enclosed space.