Removal of humic acid from aqueous solutions is pivotal to protect water from environmental and health concerns. Slurry consisting of silica gel, alumina, calcium hydroxide, and zeolite A was hydrothermally treated to prepare a hydrogarnet/ zeolite composite for humic acid removal from water. The amount of hydrogarnet formed and the partial disorder in the zeolite structure affected the porous properties of the composite. The zeolite content in the slurry influenced the humic acid adsorption capacity. The composite hydrothermally treated for 2 h showed improvement in higher humic acid adsorption capacity (9.0 mg g −1) than the composites hydrothermally treated for 6 and 24 h (7.4 and 5.9 mg g −1) based on the pseudo-second-order model. The adsorption capacity of the composite was related to its crystal phase and the lattice distortion of the hydrogarnet, not the amount of hydrogarnet formed.