1. Every once in a while check beneath all sinks in your house to see if there are any pipe leaks. Also, play close attention to slow-draining pipes as they may have blockages. In addition to these checks, it wouldn't hurt to re-caulk around sinks that appear old and/or may have began deteriorating.
2. You can check for water leaks by monitoring your water meter while all the faucets and water using appliances in your home are in the off position. For about an hour, check the meter in 4-5 minute intervals to see if there are any changes. Any water usage during this time may mean you have a pipe leak.
3. Give your self easy access to the 'MAIN' water shut-off valve in your house. By being able to quickly stop the flow of water in an emergency, you can often save yourself from further damage.
4. If your bathroom floor is tiled, make sure there aren't any cracks and/or missing areas of grout. To minimize the effect of water damage in this area,ensure that all grout is intact and sealed.
5. If your refrigerator has a built in ice-maker or water dispenser, periodically check the connecting hose for leaks. Any leaks should be taken care of immediately with a replacement hose.
6.The common source of water damage in the kitchen is caused by the dishwasher. Check the dishwasher for discolored/warped materials. Also periodically inspect the connecting hose from the dishwasher to the main water line.
7. In your bathroom check the caulking around the bathtubs and toilets. If there are any discolorations,cracks or mold, then you may have some water damage. Be sure to re-caulk any area showing these initial signs of damage.
8. It never hurts to have a working fan in your bathroom. Almost any home improvement store supplies them, and they're relatively easy to install. These will reduce any moisture and build up of mildew from running hot water.
9. If you have a washing machine in your house, inspect the connector hose every few weeks or so for any signs of damage. Even if there aren't any problems, the hose should be replaced about every 3-4 years.
10. Air conditions should be serviced by a qualified contractor every couple of years. they will be able 'fish-out' obstructions that may cause water damage in around the supporting window.
These tips are not a guarantee water damage will not occur in your home, but following these preventive measures can lessen the chance of it happening.