Repair at Garage Door Seal
Cracks and missing concrete at the point where the garage door comes in contact with the driveway creates gaps into which rain water leaks. Repairing this area can greatly decrease the likelihood of leak problems. Lie on the garage floor on a sunny day and look for any cracks with light coming from the base of the door. Fill in any gaps or cracks along the base of the door with concrete or crack filler, and allow the mix to cure before closing the door.
Driveway Slope Left to Right
Having a driveway repaved so its center is slightly higher than its left and right edges can guide rain water to run off into the lawn on either side of the pavement. Ask the driveway contractors to create a "spine" or ridge running down the center of the driveway to whisk water away from the garage.
Car Tire Grooves
Over time, especially with asphalt, driveways develop grooves where car tires sit. This creates a pair of channels in the driveway that can act as a conduit for water. Repaving the driveway is the only way to solve this problem, and may go a long way toward remedying the garage leak.
Channel Drain Grate
One option to explore for remedying drainage issue is the installation of a drainage grate beneath the garage door threshold. Drainage grates are metal grates over channels that allow water to pass through and safely drain away from the garage. This involves breaking up the pavement of your driveway just in front of the garage door, so less-invasive remedies should be attempted prior to this method.
Driveway Slope Change
If your driveway is flat or has only a slight slope toward your garage, you may be able to have your driveway broken up and repaved with a slope more appropriate for draining water away from the garage. This may be a costly solution, so other remedies should be attempted before resorting to a complete resurfacing.