An improved water purification system and method for converting contaminated water into potable water in an inexpensive and reliable manner that includes several active and passive purification components contained within a housing. The passive components may include, for example, a macro filtration unit for filtering debris; a pre-depth mixed bed media filtration unit to mechanically filter out various contaminants; and a post-depth mixed bed media filtration unit to remove particles or organic growth that may have resulted from active filtration. The active components may include, for example, a specialized media filtration unit to destroy and remove organic and inorganic contaminants; an ozonation unit to break down and destroy oxidizable matter; an active carbon filtration unit to neutralize ozone, adsorb contaminants, and improve taste; and a UV sterilization unit to destroy any remaining microorganisms and neutralize ozone.