Abstract: Sewer check valve and cleanout apparatus including a valve body, substantially inverted-T in shape, said valve body provided with a horizontal conduit and an upright external riser; an internal riser receivable within the external riser; and a flapper. The horizontal conduit of the valve body is provided with opposing end hubs for attachment to existing sewer and drainage lines and is provided, on its upstream portion with an annular valve seat about the conduit. The flapper is pivotally attached to the lowermost end of the internal riser to sealingly engage the valve seat. The internal riser, with flapper, are readily accessible for maintenance or replacement by a simple retraction of the internal riser from the external riser. The internal riser is provided with a curved bore, cooperating with a curved bore in the external riser for directing cleanout cables downstream and away from the flapper valve.