Check where the water is coming from, It may be coming from somewhere higher up, e.g. at the sink drain itself. If this is just a leak from the 'P trap', (U bend) the plastic pipe may be cracked. You will need to replace the U bend pipe but make sure the connections are only hand tight. any more than hand tight could result in spliting the pipe or cracking the connector.
Davy Mac, March 2009
