Pyrgulopsis greggi has been assessed as Vulnerable D2. This is due to the fact that the species is narrowly endemic to one location at Grapevine Creek, California, and is therefore susceptible to changes in water chemistry and groundwater flow levels that may be impacted by proposed developments in the area feeding Grapevine Creek.  Further research is urgently needed into the impacts of these proposed developments on the species, in order to determine whether a higher threat category is required.

This species is narrowly endemic in the Grapevine Creek, Fort Tejon State Historical Park, California (Hershler 1995).

This species was reported to be commonly found (Hershler 1995).

This species was found in mud and watercress in the medium-sized, moderately impacted freshwater stream of Grapevine Creek, Fort Tejon State Historical Park, California (Hershler 1995).

There were no recorded threats to the global population of this species at the time of its description (Hershler 1995). However, recent developments around the Tejon Mountain Village (2009) have been noted to change the water flow around the Lake and the outflowing Grapevine Creek, and hence, it may well have impacted this species. The report also notes the proposed plans for a golf-course and large residential development with requirements to take more groundwater for the supplies for these facilities which may also impact flow and water chemistry in the Creek.

This species is not utilised.

This species has been assigned a NatureServe Global Heritage Status of G1 - Critically Imperiled (NatureServe 2009). There are no species-specific conservation measures in place for this species, however it does occur within the Fort Tejon State Historical Park. In order to ensure that populations remain viable, future population surveys are suggested.