Tufa deposits are common in the Quaternary record. Facies developments are dependent upon localised carbonate precipitation. Generally, these take the form of phytoherm build-ups, together with associated detrital deposits derived from disagragation of the former. Phytoherm cements differ from speleothems and floë calcite accumulations in being biologically mediated or modified. This paper recognises the following five types: perched spring line, cascade, fluviatile, paludal, and lacustrine facies. Each type is composed of distinctive constructional and detrital sediment associations. These unique sediment combinations are the product of an interplay between angle of slope, water discharge rate, standing-water bodies, phytal and microbial colonization and ambient temperature. The proposed models will be of value in the interpretation of ancient and partially exposed tufas.