There are obvious causes of water damage that most people know about like plumbing leaks and leaking roofs, but what about some of the other less common causes?

Basement walls insulated with fiberglass tend to be a problem because moisture becomes trapped behind them and the air leaks that can happen in between one floor of the home and the next or even the attic.
Fiberglass absorbs water and so installing fiberglass insulation in basements is not a good idea. Installing plastic sheeting inside the wall isn't the answer, either, because this also traps moisture.

Using blue board insulation is a bit better if you're going to insulate your basement because this insulation allows moisture to move freely through the wall and allows it to dry out.

If the land around the home is sloped toward the home's foundation, this can cause problems, too. Water doesn't flow away from the home as it should and can seep into the basement or weaken the foundation and cause the house to sink slowly into the ground.

If you live in a colder climate, you should be careful to have your ceilings insulated properly because if it isn't, it can cause what are called ice dams and water will leak into the house.

Moisture that leaks up into the attic in the form of steam or humidity can attach itself to the inside of the roofing and cause it to not only rot, but mold to grow upon it, as well.In warmer climates, water damage can occur due to flaws in the air conditioner or the air ducts. Attic hatches that are not properly sealed when shut are a cause of water damage inside attics and on ceilings.

Light fixtures in the home should be airtight when they are installed, especially if they are the recessed kind and exhaust fans that aren't directed outside the house, but only into the attic can be a problem, too, whether they are from the bathroom, kitchen, or laundry room.

Any exhaust fan should have a vent to the outside of the home so moisture doesn't collect, condense, and cause the water damage you are trying to avoid.