Masonry manholes have long been designed and built because of their structural soundness, durability, economy, and minimal maintenance requirements. Although, for the most part, masonry has been supplanted by precast concrete as the predominant material for manholes, there are still situations in which brick or block are preferred. One obvious example is in the repair of existing masonry manholes. Another example is in sewer systems designed to carry chemical wastes from industrial processes. Clay sewer and manhole brick provide greater resistance against chemical attack than portland-cement-based materials do, and thus hold up better when exposed to chemical wastes. ASTM C 32 covers two grades of clay or shale manhole brick. Concrete block for manhole construction is covered by ASTM C 139. The manhole itself should be laid with Type M mortar because of its durability in below-grade construction. Contractors interested in pursuing opportunities for manhole construction should look for specifications in Division 2-Sitework in contract documents. Masonry manholes generally are specified there rather than as a separate masonry contract.