Colorado River Basin Conservation Act This bill reauthorizes the Department of the Interior to fund or participate in pilot projects to increase Colorado River System water in Lake Mead and the Colorado River Storage Project reservoirs through FY2026. Interior administers these pilot projects to address the effects of drought conditions on the Colorado River Basin, which includes the Upper Basin states (Colorado, New Mexico, Utah, and Wyoming) and Lower Basin states (Arizona, California, and Nevada). The bill also requires Interior to submit an updated report to Congress by the end of FY2027 on the effectiveness of the pilot projects and a recommendation on whether to continue the program.