Abstract: A linerless composite tank for a waste or water system on board an aerospace vehicle includes a monolithic tank body having a first composite material co-cured with a second composite material. The first composite material includes a first resin and the second composite material includes a second resin that is different from the first resin. The first composite material forms an innermost surface of the monolithic tank body defining a tank chamber of the monolithic tank body. A method of manufacturing the linerless composite tank includes providing a mold having a desired interior shape of the monolithic tank, applying the first composite material to the mold, applying the second composite material to the mold, and co-curing the first composite material with the second composite material to form the monolithic composite tank.