ShopRite and Colgate-Palmolive are staging a contest to underscore the importance of water preservation while brushing. The "Save Water Challenge" will award two Northeastern schools with lumber made from recycled materials to create an outdoor garden — encompassing up to 12 garden beds, one gazebo, one picnic table and one flat bench. Schools enlist students and other constituents to visit a promotional page within recycling company TerraCycle's website and pledge to conserve water by turning off their faucet while brushing their teeth. The prize goes to the two schools that earn the most pledges from July 8 to Sept. 30.