Water and Targeted Environmental Research Act of 2018 or the WATER Act This bill amends the Food Security Act of 1985 to modify the Department of Agriculture (USDA) Conservation Innovation Grants program. The bill modifies the program to: specify that matching funds for grants may include in-kind contributions provided by a cooperative extension service or a state agricultural experiment station, and extend through FY2023 the requirement for USDA to use specified funds for payments to producers to implement practices to address air quality concerns from agricultural operations and meet regulatory requirements. The bill also requires USDA to establish and maintain a publicly available database that provides: (1) a compilation and analysis of effective conservation practices for soil health, nutrient management, and source water protection in varying soil compositions, cropping systems, slopes, and landscapes; and (2) a list of recommended new and effective conservation practices.