A water purification apparatus connected to a water system includes a hopper for holding chemical tablets on a perforated bed and an underlying basin. A spray head is detachably connected to the perforated bed and sprays water onto the tablets and parallel to the perforated bed. The basin receives the water through the perforated bed. Because the hopper allows for the use of different spray head designs, the rate at which water is introduced to the tablets, and thus the chemical output, may be modified by replacing one spray head for another having a different number of spray nozzles or having spray nozzles of a different size or shape. Consequently, the hopper of the present invention may be used for delivering the proper concentration of a variety of water treatment chemicals.