Starting into the DIY world can be a bit intimidating, but there are few precautions that will ease the intimidation of a project. Home improvements aside, it is a must to understand how to handle a serious problem that may arise in your house during a project or natural disaster.
Water is definitely more of a threat to your home than to your health, unless combined with electricity. Water can lead to mold problems, rotten wood, and wall discoloration. A lot of times these leaks come from appliances and supply hoses. Staying on top of home maintenance and inspections can help prevent problems, but not always.
Sometimes the leak is very apparent and the source of the problem is obvious. Other times the leak is slow and the source is unknown. For appliances you can isolate the incoming water by shutting off the supply hose valve. For faucets there is usually a similar shut off valve near the fixture or under the sink. For leaks with an unknown source, shut off the main water supply valve. This valve is usually located outside for homes in warmer climates. Conversely, the valve is located inside for homes in colder climates.