Monday morning College Station Water Services found a broken wastewater line along Carter Creek in College Station. The spill area is behind SAMS Club along Associates Drive.
According to the city, the leak started when a creek bank the wastewater line was buried gave way after last weeks heavy rains.
Four million gallons have leaked into the creek.
The area potentially affected includes Carter Creek east of Associates Drive, and immediately downstream.
Crews are on site attempting to isolate the spill and prevent any more wastewater from entering the creek. A temorary fix should be in place first thing Tuesday morning.
The Texas Commission on Environmental Quality has been notified.