This invention relates to a method of protecting concrete sewer pipe, manholes, lift stations, pump stations, wet wells, sewage treatment plant components, and septic tanks and/or septic tank components comprising coating said concrete items by rolling, spraying, or brushing on a coating system consisting essentially of a primer, intermediate coat and topcoat. Each coat is a polymeric coating prepared in situ by combining a hardener with a prepolymer formulation. The pepolymer is an amine-containing material, resulting in a polyurea-based coating. The chief advantages of the coating are that it can be applied utilizing conventional, simple equipment, and the increased drying time allows for excellent adhesion on the substrate. Also, it is a tough elastomeric material resistant to attack by water or the sulfuric acid microbial metabolic end-product.