Inspected water distribution system for water leaks. Water main passed a leak test, showing no leaks. Whole house passed a leak test, showing no leaks on either hot or cold side. Whole house passed a pressure loss test, pressure held for 10mins with the water off. Found no leaks on the plumbing system. Speculation: The water damage done to the floor under the window in the front bedroom seems to be either a leak from the window or from the concrete. The landscaping around the house forces the front lawn to hold a lot of water when it rains (a big bowl). It was also noticed that most of the dark spots shown were under a wall and near door thresholds with screws in them. Maybe foundation? Found that the water heater was installed poorly and not up to code. Gave estimate to correct.