The water in Medina Lake has fallen so low that the San Antonio Water System is no longer drawing water from it. The shift will affect the water source for the southern portion of Bexar County.
At the end of last week, SAWS shut off its pump in Medina Lake, which is now only five percent full.
"The water remaining is developing some water quality issues," said SAWS Spokeswoman Ann Hayden.
The decision to stop pumping was due to a concern about the water quality level and the amount of algae.