Water leaks! Different diagnoses

Hello guys, My Passat TDI 110 HP Bj.98 KM 135 Tsd. loses a lot of water last time. First diagnosis at ATU was that there was a leaking engine and a flange was not dense. It was replaced. About 2 months quiet had. Now it starts again, but sometimes no water tracks to see. After highway ride the whole content is consumed. On city trips very little. According to ATU after a pressure test a case for VW. Suspect on head seal. Was at the VW they have under the container (on the vessel Body lime drip traces discovered) VW was the first to diagnose water pump and if I had bad luck, the head seal could also be defective. It recommended me to start with the replacement of water pump. After driving home I looked again under the tank and discovered about 10 fresh drip traces.On this I looked with my hand on leaks.On the surface below of container was moisture. What do you mean it could be. I am m I’ll be very grateful if you can help me.