Leaking boat

Recently I have noticed that water is gathering under the engine.  The boat has been stationary at the dock since October. I have tried to taste the water, and I think it is fresh water. The boat lies in an area where there is brackish water so I can't be 100% sure. Another thing that support the theory that the water comes from the sky and not from the ocean is the fact that it seems to collect more water under the engine when it rains. 

Does anyone had similar problems or some suggestions to where the leak might be located?
If it's not rainwater, it has to be the propeller-shaft, right?

Lasse

High
If its connected to rain, I'll recommand first to check the seal of the hand pump on the deck (I changed the seal and add a cover, see www.clubfeeling1090.fr/forum/feeling-109...cement-pompe-de-cale ). After I'll check all bolts through deck in the stern area.
Best regards

François

Hi.

We have located the source for one of the leaks. It seems like the hot water tank is leaking. Are there any suggestions, how to drain this? I guess we have to remove it from the boat and inspect it. 
If we turn off the water pump, and drain it through the valve indicated at the attached picture, hot water drains out in the keel. Is this the correct way of doing it? Then just remove all the hoses when the water stops flowing?

Picture:  ibb.co/QdX9Vwg