The Temecula Basin is a basin of down faulted Mesozoic basement rock, overlain by late Cenozoic continental sediments.
It is the largest groundwater basin in the San Diego water region.
[2] This aquifer is recharged by precipitation in the valley, underflow and by surface flow from the creeks draining the surrounding mountains and the southern Perris Block in the watershed of Murrieta Creek and Temecula Creek, tributaries of the Santa Margarita River.
[3][4] In 1919, a USGS Water Supply Paper described the Temecula Basin:
This Riverside County, California-related article is a stub.