I just installed a new double bowl sink and have a problem. When there is water in both bowls, it drains very slowly. Water in just one bowl OK. One thing I did not do was add a tail piece to the trap before attaching the 'double' drain pipe. Could it be that there is not enough length from the trap bottom to the curve of the drain or could it be something else? :confused:

Hey Gazzzz,

When you drain from just one tub the other tub acts as a vent allowing the water to drain freely. However, when both tubs are full and you try to drain them both it has nowhere to vent and will not drain as fast as suction holds it back. This is normal and not too much to worry about. Cheers, Tom