If water is leaking from the trigger of the spray gun it means that a seal has gone when you pull in the trigger. If water is leaking from the body of the spray gun this can be caused by a small pinhole on the seams.
This will require a replacement spray gun for your machine, if your machine is within the warranty period this can be sent to you free of charge under your warranty, if your machine is out of warranty then a replacement spray gun can be purchased on our website.