A gravity flow drain extension is adapted for attachment to an exit opening of a condensation drain line. The drain extension includes an extension line for receiving and transporting water. The open connecting end of the extension line is attached to the exit opening of the condensation drain line, such that water exiting the condensation drain line enters the extension line. The extension line defines at least one discharge opening downstream of its connecting end for dispensing water at a location away from the exit opening of the condensation drain line. A backflow preventer upstream of the at least one discharge opening prevents backflow of water into the condensation drain line.