Turbidity heads for a turbidity sensor or probe and the resulting sensor are disclosed that include a light source providing an outgoing light ray, a photodetector capable of detecting an incoming light ray; an isolator separating the light source from the detector portion; and a first reflector in the path of either the outgoing light ray or the incoming light ray. The first reflector is positioned to reflect either the outgoing light ray or the incoming light ray to achieve a measurement angle defined between the outgoing light ray and the incoming light ray of ninety degrees plus-or-minus two and a half degrees to comply with the standard ISO 7027 for turbidity measurement.