Check the listing for details. First Flush Downspout - First Flush Diverter Kit, Suits 3" Round Pipes. Condition: New. Listed at 84.50 USD. FIRST FLUSH: Divert the initial runoff to ensure only the highest quality water is captured. JUST ADD PIPE: The First Flush with Catch All Tee includes everything you need to install - just add 3" pipe for the chamber.