A water heater flushing system includes a housing having an inlet configured to be coupled to a drain port of the water heater and receive water therefrom, and an outlet configured to discharge water from the housing. A series of filter elements are positioned and spaced apart within the housing transverse to a water flow path defined between the inlet and the outlet, the series of filter elements are configured to separate solid impurities from the water according to different particle sizes (e.g. progressively different or finer particle sizes) in the water flow path between the inlet and the outlet. A viewing feature, such as a transparent lid, is carried by the housing and configured to provide visual access to an interior of the housing for inspection of separated solid impurities at each of the filter elements. A sediment buster may be coupled to the inlet of the housing and configured to send a fluid into the drain port of the water heater. The sediment buster may include a fluid supply device, and shut-off valve between the fluid supply device and the inlet of the housing.