The Houston Chronicle reported Thursday that the preliminary notification came this week to the San Jacinto River Authority. No formal request has been made.
Houston owns two-thirds of the reservoir's water rights. The river authority holds the rest. The additional water, through a dam release, would flow downstream to Lake Houston and feed the city's nearby water purification plant.
Lake Conroe's level Thursday was about 197 feet, or 4 feet below normal.
River authority official Jace Houston says the lowest the level has dropped is 5 feet below normal in 1989, the only other time Houston sought additional releases.